Analytical extensions-themed posts expand on material that has appeared in another newsletter/section and other parts of this website more generally.

A previous post explained how the sharp downturn in bilateral relations between China and Japan following the political ascent of Sanae Takaichi, which comes amid an ever-intensifying military-technological competition between China and the United States, may lead China to, in effect, maximally turn the proverbial screws on Japan. One of the approaches that Beijing can undertake entails what is best understood as the activiation of the Sea of Japan threat vector, a dynamic of exceptional military signifiance that has long remained dormant not as a result of anything that Japan or the United States have done or could have done but because Beijing decided—out of self-interest—to restrict the geographic scope of China-Japan and China-United States military competition. While previous SPAS Consulting analyses have broached this topic, this post will offer a concrete example of one way China may activate the long-dormant Sea of Japan threat vector.

As explained in the first of the above posts, Japan is significantly closer to China’s northeast than the rest of the country:

A distance of just ~600 kilometers separates China’s northeastern Heilongjiang province from the northernmost tip of Hokkaido, while just ~700 kilometers separates said Chinese province from the southernmost tip of Hokkaido. Just ~750 kilometers separates China’s northeast from the northernmost tip of Honshu, while just ~810 kilometers separates China’s northeast from the westernmost point of Honshu. Tokyo is just ~1100 kilometers from China’s northeast, while the easternmost part of the Kanto Plain bordering the Pacific Ocean is around 1170 kilometers from China’s northeast. For context, Tokyo is around 1550 kilometers from the easternmost point of China’s Shandong Peninsula, while Tokyo is around 1750 kilometers from Shanghai. Sapporo, meanwhile, is over 1700 kilometers from the easternmost point of China’s Shandong Peninsula, while being over 2170 kilometers from Shanghai.

Given these distances, China can readily employ combat aircraft equipped with standoff land-attack and/or maritime strike munitions to target Japan’s western coast, as well as the rest of the elongated but quite narrow archipelagic country. There is, however, a catch:

China is separated from the Sea of Japan by a distance of just ~10.3 kilometers in orthodromic terms, with the Tumen River flowing for another ~16.5 kilometers from the easternmost point of the China-Russia border until it reaches the Sea of Japan.

By launching ballistic missiles and/or boost-glide vehicles (BGVs, also known as hypersonic glide vehicles, or HGVs) like the DF-17, China can overcome the fairly minor complication of having aircraft very briefly traverse North Korean and/or Russian airspace to reach the Sea of Japan, but China increasingly has an alternative: it can employ low-observable—so-called “stealth”—uncrewed aircraft to undertake such politically sensitive missions without putting at risk a Chinese pilot.

One example of such a Chinese uncrewed aircraft is the GJ-11, which was formally unveiled at a 2019 military parade in Beijing (the carrier-based naval variant, the GJ-21, was one of several large uncrewed aircraft designs displayed at the September 2025 military parade in Beijing).

A reusable armed uncrewed aircraft in the vein of the GJ-11 can be readily used—in time of war—to take off from one of several suitable Chinese airbases in the country’s northeast, transit through North Korean and/or Russian airspace for 2-4 minutes so as to reach international airspace in the Sea of Japan, and transit toward a pre-programmed position from which to launch stand-off munitions against Japan before returning to base and restarting the cycle.

Large uncrewed aircraft such as the GJ-11 can be employed in a manner that is conceptually akin to a reusable cruise missile that launches less expensive shorter-range strike munitions. The GJ-11 has previously been captured on satellite imagery at an airbase in the Himalayas near India, one of several sectors in which the GJ-11 and other Chinese uncrewed aircraft designs are likely to significantly enhance the reach and strike capabilities of the People’s Liberation Army Air Force (PLAAF) over the coming decade.

The activation of the Sea of Japan threat vector and the use of uncrewed aircraft like the GJ-11 to attack targets across the Japanese archipelago via the Sea of Japan is unlikely to constitute a silver bullet for China. Japan is, in both qualitative and quantitative terms, an immensely capable country, not least when it is allied to the United States, which has forward-deployed military forces in Japan and, as such, tremendous equities in the integrity of Japanese airspace. The activation of the aerial component of the long-dormant Sea of Japan threat vector, which has distinct air-to-air combat, terrestrial strike, and maritime strike components that are beyond the scope of this brief analysis, nevertheless has the potential to profoundly undermine Japanese security.

It bears emphasis that the potential activiation of the Sea of Japan threat vector will come at a time of intensifying military-technological competition between China and the United States, which is already stressing Japan’s ability to keep up in, among areas, air-to-air combat capabilities and naval air defence capabilities, areas in which the potential deployment of uncrewed aircraft such as the GJ-11 above the Sea of Japan is likely to only compound the immense challenges that Japan already faces.

https://www.spasconsulting.com/p/report-indicates-that-china-has-launched

As the above post explained, much rests on the maturity and competitiveness of the new Type 095-class SSN, and exceedingly little information is publicly available about the Type 095-class design at this time. In the absence of information, the above post identified several important areas of uncertainty and raised questions to be answered as new information is uncovered and rendered available. This post broaches the potential implications of a new Chinese SSN design of currently unknown characteristics and performance for Japan. Japan has much to lose if China experiences a major qualitative and/or major quantitative expansion of its undersea warfare capabilities, something that a new and potentially much-improved SSN can offer the People’s Liberation Army Navy’s (PLAN) current submarine fleet.

While Japan has long encountered a large fleet of Chinese submarines, China only operated non-competitive diesel-electric submarine (SSK) designs into the 1990s. Although the situation progressively changed over the course of the 1990s and through the ca. 2010 timeframe, the PLAN submarine fleet remained composed of increasingly more capable but nevertheless qualitatively limited SSK designs. The introduction of the Chinese-built Type 039A-class design (U.S. ONI: Yuan-class) amounted to a major qualitative breakthrough for the PLAN, and a major quantitative breakthrough as it was built and deployed versions of this Chinese SSK design in increasing numbers into the 2020s. The Type 039A-class, and its successor, the significantly altered Type 039C-class (U.S. ONI: Yuan-class mod), nevertheless remain large ocean-going SSKs optimized for operations in the deep waters of the western half of the Philippine Sea with the aim of enhancing China’s maritime strike capabilities by serving as forward sensor nodes and anti-ship missile launchers.

To this end, China developed and deployed not only the YJ-18 cruise missile—a primarily subsonic design with a terminal stage rocket-boosted sprint vehicle—but also the recently unveiled YJ-19, which appears to be a scramjet-powered supersonic anti-ship missile that can be launched out of a standard 533 mm diameter torpedo tube.

https://www.spasconsulting.com/p/unveiling-of-six-new-chinese-anti

With public indications that Chinese submarines are increasingly being employed as forward sensor nodes and anti-ship missile launchers by the PLAN, it bears emphasis that the threat that Chinese submarines can pose to the JMSDF, U.S. Navy and others is very different than the torpedo-centric submarine threat of popular imagination. A Chinese submarine may, using external target location data, launch an anti-ship missile at a target ship that is located several hundred kilometers away, which is to say far beyond the maximum detection range of a warship’s sonars and beyond the maximum range of its ship-based anti-submarine armament. This approach amounts to a qualitatively distinct threat to the JMSDF, one that the Japanese surface fleet is not currently optimized to counter in multiple respects:

https://www.spasconsulting.com/p/japans-navy-is-poorly-positioned

Although China has built and deployed a steadily expanding fleet of second-generation Type 093-class (U.S. ONI: Shang-class) nuclear-powered attack submarines (SSNs) over the past twenty or so years, what little information is available in the public domain strongly indicates that even the latest Type 093B-class SSNs leave much to be desired. China and the PLAN seemingly agree, given the development and reported launch of the first Type 095-class SSN hull, which is presumably the successor to the long-running Type 093-class design.

Whatever the presumed qualitative attributes of the Type 093-class, not least vis-a-vis the formidable anti-submarine warfare capabilities of both the Japan Maritime Self-Defense Force (JMSDF) and the U.S. Navy (USN), the fact remains that—uncertainties about the total number of Type 093-class hulls in existence notwithstanding—the Chinese SSN fleet remains very small. This limits how many Chinese SSNs of any given design may be deployed at sea on any given day and, as such, the practical reach of China’s SSN force, which is incomparably better-suited to undertaking long-range and long-endurance deployments, including deployments around the Japanese archipelago and the maritime approaches thereto.

Whatever the presumed—in the absence of credible information—qualitative attributes of China’s new Type 095-class SSN design, which presumably amounts to an improvement over the preceding Type 093B-class design, the advent of a new Chinese SSN design presents a very major potential threat to Japan, even if the Type 095-class remains significantly inferior in terms of various qualitative attributes relative to the latest American Virginia-class SSNs. The reasons for this are straightforward.

• China made major investments toward expanding the Bohai Shipyard, which specializes in building nuclear-powered submarines, in the 2010s—to what end, one must ask.

• SSNs remain a glaring area of both qualitative and quantitative shortcomings for the PLAN, which has closed capability gaps in many important areas vis-a-vis both Japan and the United States.

• The PLAN requires a large fleet of SSNs if for no other reason than to improve the anti-submarine capabilities of China’s expanding number of aircraft carrier groups and surface action groups, let alone to undertake long-range deployments in distant waters or, more to the point of this post, operate around the Japanese archipelago and along the maritime approaches to Japan, particularly for vessels going to/from North America.

China’s new Type 095-class SSN may or may not be very competitive relative to the ever-moving dynamic target set by American submarine technology. The Type 095-class may, however, be good enough for Beijing to allocate the resources required to make full use of the much-expanded production facilities at the Bohai Shipyard. This can result in a situation in which the PLAN may deploy a greatly expanded SSN force over the course of the 2030s.

While one can indulge in speculation as to how many new Type 095-class SSNs the PLAN may come to deploy, for the present purposes, it should suffice to say that the ability to maintain even a single SSN on station around the Japanese archipelago and the maritime approaches thereto will constitute a new type of threat for Japan, which has long staked much on its ability to interdict Chinese endurance-constrained SSKs as these transit the Miyako Strait and other channels along Japan’s Ryukyu Islands Chain to reach the Philippine Sea and, no less importantly given the fact that SSKs do not have nuclear propulsion, return back to port to refuel, resupply, and rearm. An expanded Chinese SSN force will introduce a new dynamic: Chinese submarines that may be detected in the favourable underwater geographic along the Ryukyu Island Chain, along which Japan has long established undersea acoustic sensors, only to break free into the open waters of the Pacific Ocean and, for example, patrol the maritime approaches to Tokyo Bay, or even undertake patrols in the vicinity of the Aleutian Islands in the North Pacific so as to interdict ships transiting to/from the western coast of North America.

A significantly expanded Chinese SSN force will constitute a qualitatively new and distinct threat to Japan, even if China’s new Type 095-class SSNs remain significantly inferior to the latest American Virginia-class SSNs. Here, as elsewhere, the fact remains that China does not always need perfect or world-leading military systems to significantly alter the regional military balance in its favour. Needless to say, the more competitive the new Type 095-class SSN is relative to the latest in American submarine technology, the greater the challenge that Japan will face in securing its maritime approaches in times of crisis and war in the 2030s and beyond. Japan has, for decades, been able to use forward-sensor and anti-submarine capability barriers to greatly blunt, if not neutralize, the threat posed by Soviet, Chinese, and North Korean submarines. The mere prospect of a large fleet of potentially far more competitive Chinese SSNs should raise alarm bells in Tokyo unless Japanese officials are aware of some fundamental qualitative shortcomings of the new Chinese Type 095-class SSN design that will significantly constrain its military implications for Japan without being sensitive to how many China comes to build and deploy over the coming years.

In the absence of information, observers tend to speculate, but serious analysts endeavour to identify important areas of uncertainty and raise questions to be answered as new information is uncovered and rendered available at a later date. This SPAS Consulting analysis merely presumes that the new Type 095-class will constitute a qualitative improvement of some sort over the preceding Type 093B-class SSNs and that China may find the Type 095-class design to be satisfactory enough to make full use of the much-expanded facilities of the Bohai Shipyard, which is the only Chinese shipyard to build “full-size” nuclear-powered submarines. There are very major analytical uncertainties at play, and the fact remains that Japan has the most to lose in the event of any major qualitative and/or quantitative advances in China’s undersea warfare capabilities.

Some additional questions to consider:

• Will the JMSDF be forced to hold its SSKs and anti-submarine warfare aircraft, helicopters, and warships “in the rear,” such as around the approaches to Tokyo Bay and the Seto Inland Sea, in order to counter a prospectively qualitatively and/or quantitatively enhanced Chinese SSN force?

• What implications will such a development have on Japan’s ability to prosecute its preferred war plans alongside the United States? Being forced into a defensive posture while having one of the world’s longest coastlines as an archipelagic nation is unlikely to be a welcome development for Tokyo.

• What implications will the Type 095-class have in other sectors, above all around the Aleutian Islands in the North Pacific, which are part of Alaska? Japan has long been able to take the security of its maritime lines of communication with North America for granted in the absence of a qualitatively and/or quantitatively significant Chinese SSN fleet.

• The Type 095-class and future Chinese nuclear-powered submarines that draw upon, and perhaps expand upon, whatever qualitative advances it encompasses relative to preceding Chinese nuclear-powered submarines, may have a significant land-attack capability. Japan’s current air defence and ballistic missile defence architecture is optimized against threats that approach Japan from the northwest, west, and southwest. Chinese strike munitions that approach Japan from the east may bypass Japan’s current defences, and require significant adjustments and resource allocations. Here also, submarines constitute a lot more than a means of launching torpedoes.

Minimal comment-themed posts are used to introduce data points for use in other posts going forward. Posts of this theme will typically feature minimal analysis and commentary.

Japan’s Sakishima Islands, which refer to a subset of the larger grouping of the Ryukyu Islands Chain, constitute prime “real estate” in the Western Pacific. These Japanese islands are home to expanding Japanese military garrisons, and Tokyo is working on plans to evacuate the 100,000 or so civilians who reside in the Sakishima Islands during a crisis before these far-flung outposts of Japanese military power become war zones.

As explained with respect to China’s possible activation of the Sea of Japan threat vector, geography plays a key and often underappreciated role in the fast-evolving China-Japan and China-United States military balance. Technological change is, in effect, making the far-flung Sakishima Islands “increasingly proximate” to China.

The Sakishima Islands are just ~400-550 kilometers from mainland China, 270-510 kilometers from the southern tip of Okinawa island, and ~850-1050 kilometers from the southern tip of Kyushu. Military facilities and militarily relevant infrastructure on the far-flung Sakishima Islands are increasingly exposed to Chinese attack. These small islands, the largest of which is Miyako Island, are not and will never be garrisoned by a fairly dense array of air defence and ballistic missile defence capabilities in the manner of Kadena airbase and other military facilities on Okinawa Island.

An orthodromic distance of just ~400-550 kilometers from mainland China places the Sakishima Islands within range of a wide range of existing Chinese strike capabilities, including stand-off munitions launched from Chinese combat aircraft. It also places the Sakishima Islands within range of a diverse array of “new” strike capabilities, whether propeller-driven fixed-wing strike drones in the vein of the Iranian Shahed-136, low-cost cruise missiles, powered guided glide bombs, and even armed uncrewed surface vessels (USVs).

The isolated Japanese military outposts in the Sakishima Islands are likely to be subject to intense and regular bombardment both at the outset and over the course of a major war. Chinese and Japanese military planners, as well as their American counterparts, are likely to recognize how important it is for Japan to occupy this real estate, which offers land on which to position a wide range of both lower-end and higher-end sensors that can be used to detect Chinese aircraft, surface ships, and even submarines. While the military value of the Sakishima Islands is not in question, the fact remains that these far-flung outposts of Japanese military power are exceptionally and increasingly vulnerable to Chinese strike capabilities.

Commentary-themed posts are intended to broach or highlight a specific issue, not limited to recent and ongoing events. These posts will typically be much shorter and less detailed than analysis-themed posts.

Something very unusual transpired on 30 March 2024. Japan’s Joint Staff Office announced that a Chinese military aircraft, which in this case happened to be an uncrewed aircraft design, was observed flying in international airspace over the Sea of Japan.

The Chinese uncrewed aircraft in question is reported to have been a WZ-7, a high-altitude jet-powered high-end fixed-wing uncrewed intelligence, surveillance, and reconnaissance (ISR) aircraft design operated by the People’s Liberation Army Air Force (PLAAF) that is broadly analogous to the American RQ-4 Global Hawk, three specimens of which have been ordered for the Japan Air Self-Defense Force (JASDF).

While Japan’s Joint Staff Office has disclosed what appear to be exceptionally irregular WZ-7 flights in the international airspace above the East China Sea and the Philippine Sea both before and after 30 March 2024, the 30 March 2024 flight of a WZ-7 remains exceptionally notable as the sole publicly documented case of a Chinese large fixed-wing military aircraft flying in the Sea of Japan outside the specific and highly transient context of bilateral China-Russia bomber aircraft training flights.

The ascent of Sanae Takaichi to the position of Prime Minister of Japan has been accompanied by a very sharp downturn in bilateral relations between China and Japan. While Japan has experienced an ever-worsening security environment vis-a-vis China over the past fifteen or so years, it is only accurate to state that China has, to date, not played all its cards so as to maximally turn the proverbial screws on Japan. One of the approaches that Beijing can undertake entails what is best understood as the activiation of the Sea of Japan threat vector, a dynamic of exceptional military signifiance that has long remained dormant not as a result of anything that Japan or the United States have done or could have done but because Beijing decided—out of self-interest—to restrict the geographic scope of China-Japan and China-United States military dynamics.

Chinese naval activity in the Sea of Japan remains exceptionally rare, with the deployments of People’s Liberation Army Navy (PLAN) vessels into the Sea of Japan being primarily undertaken so as to facilitate transits to Russian ports that host bilateral China-Russia naval exercises.

With the exception of the 30 March 2024 incident involving a WZ-7 uncrewed aircraft flying in international airspace over the Sea of Japan, the few instances of publicly disclosed PLAAF aircraft activity over the Sea of Japan can be tied to bilateral China-Russia aerial exercises.

As highlighted in an October 2025 SPAS Consulting analysis that examined the military implications of the hypothetical collapse of the Russian state on the China-United States military balance—and, by association, the China-Japan military balance, a very small amount of land separates China from the Sea of Japan. Specifically, China is separated from the Sea of Japan by a distance of just ~10.3 kilometers in orthodromic terms/as the crow flies, with the Tumen River flowing for another ~16.5 kilometers from the easternmost point of the China-Russia border until it reaches the Sea of Japan. In other words, China may not border the Sea of Japan and has no direct port access to the Sea of Japan, but just a very small amount of land determines this.

The 30 March 2024 flight of a PLAAF WZ-7 uncrewed aircraft over the Sea of Japan could not have taken place with a very brief overflight of North Korea and/or Russian territory. Although the answer to the obvious question of whether Beijing formally sought and received permission to undertake such a flight from Pyongyang and/or Moscow is not public knowledge, the seminal incident from March 2024 should highlight a simple truth: Beijing can activate the Sea of Japan threat vector if and when Chinese decision-makers wish to do so.

It bears emphasis that the activation of the Sea of Japan threat vector is not merely about potential PLAAF aircraft flights over the Sea of Japan. A “full-activation” of this long-dormant threat axis/threat vector may also entail the deployment of People’s Liberation Army Rocket Force (PLARF) missile launch brigades across the PLA’s Northern Theater Command (NTC), a sector that Beijing has long deprioritized largely out of self-interest.

Given the longstanding dispositions of the PLARF’s conventionally-armed missile launch brigades, many observers appear to understandably conceptualize the threat posed by said Chinese missiles as being one that approaches Japan from the west and southwest. Should Beijing activate the Sea of Japan threat vector, however, Chinese ballistic missiles, cruise missiles, and boost-glide vehicles (BGVs, also known as hypersonic glide vehicles or HGVs) will approach Japan from the northwest.

A distance of just ~600 kilometers separates China’s northeastern Heilongjiang province from the northernmost tip of Hokkaido, while just ~700 kilometers separates said Chinese province from the southernmost tip of Hokkaido. Just ~750 kilometers separates China’s northeast from the northernmost tip of Honshu, while just ~810 kilometers separates China’s northeast from the westernmost point of Honshu. Tokyo is just ~1100 kilometers from China’s northeast, while the easternmost part of the Kanto Plain bordering the Pacific Ocean is around 1170 kilometers from China’s northeast. For context, Tokyo is around 1550 kilometers from the easternmost point of China’s Shandong Peninsula, while Tokyo is around 1750 kilometers from Shanghai. Sapporo, meanwhile, is over 1700 kilometers from the easternmost point of China’s Shandong Peninsula, while being over 2170 kilometers from Shanghai.

Simply stated, the entirety of Hokkaido and Honshu are much closer to China if and when Beijing decides to activate the long-dormant Sea of Japan threat vector. Should China decide to do so, it will be able to launch shorter-range—and, all else being equal, less expensive and, as such, more plentiful—missiles against targets across the primary landmasses of the Japanese archipelago. As China-Japan relations further detioriate, the seemingly one-off 30 March 2024 incident in which a Chinese WZ-7 uncrewed aircraft flew in international airspace over the Sea of Japan may come to be seen as a harbinger of a new normal that has the potential to profoundly undermine Japanese security and greatly expand the challenges that both Japan and the United States face in terms of air defence and ballistic missile defence.

Commentary-themed posts are intended to broach or highlight a specific issue, not limited to recent and ongoing events. These posts will typically be much shorter and less detailed than analysis-themed posts.

Japan intends to evacuate civilians residing in the Sakishima Islands in the event of a major cross-Taiwan Strait crisis or conflict. Relocating some 100,000 civilians of all age groups from the Sakishima Islands—which constitute a subset of the larger grouping of the Ryukyu Islands Chain and notably do not encompass the heavily populated island of Okinawa—to the primary landmasses of the Japanese archipelago will likely require what amounts to an all-of-government effort supported by the privately-owned shipping and aviation sectors. Tokyo will, however, likely also require support from another unexpected source: cooperation, whether tacit or explicit, on the part of Beijing, which will inherently be capable of taking full advantage of Japan’s moment of great vulnerability should it wish to do so.

Evacuating some 100,000 civilians from Japan’s Sakishima Islands will be no easy feat, even if these small islands featured airport facilities large enough to accommodate multiple wide-body aircraft, each capable of seating some 300 persons per flight. The Japanese government will almost certainly have to charter, if not requisition, ferries and other civilian-operated merchant vessels, not limited to those operating in the Sakishima Islands and the broader grouping of the Ryukyu Islands. While the Japan Martime Self-Defense Force (JMSDF) and the Japan Air Self-Defense Force (JASDF), as well as the civilian Japan Coast Guard (JCG), will doubtless be called upon to both facilitate such an undertaking and, no less importantly, to escort the vessels of various sizes full of civilians undergoing evacuation, the fact remains that the “evacuation ship” will be an enticing target for Beijing both as it approaches the Sakishima Islands to embark civilians being evacuated, and, more grimly, as said vessels with embarked civilians depart the Sakishima Islands.

All things considered, this envisaged evacuation operation will be a very high-stakes undertaking for Japan. The politcal and humanitarian imperatives of evacuating civilian non-combatants from small islands that are likely to become warzones is wholly understandable, but Tokyo will be assuming considerable operational risk should it decide to task a significant portion of the Japanese surface fleet and combat aircraft fleet toward suporting said evacuation operation in a context in which the military incentives will be to disperse and stay further away from China during what could rapidly transition into the opening phase of the China-Japan portion of a larger war.

The Sakishima Islands are just ~400-550 kilometers from mainland China, 270-510 kilometers from the southern tip of Okinawa island, and ~850-1050 kilometers from the southern tip of Kyushu. Unlike American and Japanese military facilities on Okinawa Island, the Sakishima Islands are highly exposed to Chinese attack. As a result, there is a case to be made that Japan requires at least Beijing’s tacit cooperation to carry out the evacuation of civilians from the Sakishima Islands, let alone from Okinawa Island and elsewhere in the Ryukyu Islands Chain.

It bears emphasis that the evacuation of civilians from the Sakishima Islands appears set to simultaneously take place alongside the deployment of military reinforcements to the Sakishima Islands. Beijing may well decide to press its advantage in Japan’s moment of great vulnerability, not least if the Japanese vessels heading toward the Sakishima Islands to evacuate the civilian population will also be delivering military reinforcements to these islands.

It is only fair for observers to ask why Beijing would decide to be magnanimous and not take full military advantage of Japan’s moment of great vulnerability. The civilians inhabiting the Sakishima Islands and the rest of the Ryukyu Island Chain more generally are, in effect, automatically hostage to Beijing’s mercy, and Beijing will, in the lead up to, let alone during, a war, have free reign to choose between being merciful or taking full advantage of an excellent opportunity to sink a great many Japanese ships and aircraft, whether military or civilian. It bears emphasis that even the mere possibility of China targeting the Japanese evacuation operation will inherently raise the potential cost that Japan will pay for intervening in a cross-strait conflict. Here, it is worth considering that more than 1.5 million civilians inhabit the Ryukyu Island Chain, which is to say some 1.2% of Japan’s total population.

While Japan’s plans to evacuate its civilian population from the Sakishima Islands have caught the attention of news media and foreign observers, the fact that Japan will inherently require at least China’s tacit cooperation has not. Beijing may well decide to press its advantage in Japan’s moment of great vulnerability, and the political and humanitarian imperative of evacuating civilians from what will likely become a warzone may end up becoming a military disaster for Japan, one that may shape the course of a war.

It should be noted that military and non-military vessels used to evacuate civilians from the Sakishima Islands will require naval escorts in a context in which the Japanese surface fleet has considerable qualitative and quantitative deficiencies vis-a-vis China’s ever-evolving and increasingly formidable maritime strike capabilities. The Sakishima Islands are just ~400-550 kilometers from mainland China, 270-510 kilometers from the southern tip of Okinawa island, and ~850-1050 kilometers from the southern tip of Kyushu.

Minimal comment-themed posts are used to introduce data points for use in other posts going forward. Posts of this theme will typically feature minimal analysis and commentary.

Japan intends to evacuate civilians residing in the Sakishima Islands in the event of a major cross-Taiwan Strait crisis or conflict. Relocating some 100,000 civilians of all age groups from the Sakishima Islands—which constitute a subset of the larger grouping of the Ryukyu Islands Chain and notably do not encompass the heavily populated island of Okinawa—to the primary landmasses of the Japanese archipelago will likely require what amounts to an all-of-government effort supported by the privately-owned shipping and aviation sectors.

Transport and amphibious warfare ships operated by both the Japan Maritime Self-Defense Force (JMSDF) and Japan Ground Self-Defense Force (JGSDF) are likely to not only be tasked with supporting the evacuation of civilians from the Sakishima Islands but also transporting military reinforcements from elsewhere in the Japanese archipelago to the Sakishima Islands—public indicators suggest that the recently expanded Japanese military garrisons in the Sakishima Islands will remain in place in the lead up to and during a major conflict.

While the Japanese government will almost certainly have to charter, if not requisition, ferries and other civilian-operated merchant vessels, not limited to those operating in the Sakishima Islands and the broader grouping of the Ryukyu Islands, it will likely also draw upon a series of new vessels built for and operated by the JGSDF, namely the Nihonbare-class medium landing ships and the larger Yoko-class transport ships.

These gray-hulled military vessels are notably operated by the JGSDF rather than the JMSDF, but are subordinate to a joint JMSDF and JGSDF Maritime Transport Group based at Kure. These and other military and civilian/merchant vessels flying the Japanese flag will likely be tasked with delivering larger and heavier types of equipment to military garrisons across the Ryukyu Islands Chain, including the Sakishima Islands, in the event of a cross-Taiwan Strait crisis that may be a prelude to a major war that involves Japan.

While these JGSDF-operated ships will likely be used to transport important types of military equipment, such as a Type 03 Chu-SAM medium-range air defence system to the Sakishima Islands, it bears emphasis that the gray-hulled Nihonbare-class and Yoko-class are essentially defenceless against any form of aerial or subsurface attack. These vessels will require naval escorts in a context in which the Japanese surface fleet has considerable qualitative and quantitative deficiencies vis-a-vis China’s ever-evolving and increasingly formidable maritime strike capabilities. It should be noted that the Sakishima Islands are just ~400-550 kilometers from mainland China, 270-510 kilometers from the southern tip of Okinawa island, and ~850-1050 kilometers from the southern tip of Kyushu.

The evacuation of civilians from the Sakishima Islands appears set to simultaneously take place alongside the deployment of military reinforcements to the Sakishima Islands. As explained in another post, Beijing may well decide to press its advantage in Japan’s moment of great vulnerability, not least if Japanese vessels heading toward the Sakishima Islands to evacuate the civilian population will also be delivering military reinforcements to these islands.

Commentary-themed posts are intended to broach or highlight a specific issue, not limited to recent and ongoing events. These posts will typically be much shorter and less detailed than analysis-themed posts.

This post is intended to broach a specific question: what will the Japan Coast Guard (JCG) do in the event of a major conflict in the Indo-Pacific that involves China, Taiwan, Japan, and, presumably, the United States? Tokyo cannot afford to overlook the potential wartime role(s) that an organization home to more than 14,000 trained, able-bodied personnel—including many mariners and aviators—can play during a hypothetical major conflict in which Japan will likely have to muster all of its sources of national strength.

The JCG, which was established as the Maritime Safety Agency in 1948, emerged from the proverbial ashes of the Imperial Japan Navy. Coast guard-type organizations exist in a variety of flavours. The JCG is formally a civilian coast guard organization subordinate to Japan’s Ministry of Land, Infrastructure, Transport and Tourism. In this important respect, the JCG differs from the explicitly paramilitary U.S. Coast Guard (USCG)—which is subordinate to the Department of Homeland Security in peacetime and the Department of Defense in times of war—and the explicitly paramilitary China Coast Guard (CCG)—an organization that is part of the paramilitary People’s Armed Police (PAP) and reports to China’s Central Military Commission (CMC) in the same manner as the People’s Liberation Army (PLA).

While formally a civilian organization that is neither administratively subordinate to Japan’s Ministry of Defense nor under the operational control of the Japan Self-Defense Forces, the JCG nevertheless operates a non-trivial number of (very modestly) armed patrol ships—a development that notably long predates more recent tensions with China over Japanese-controlled features in the East China Sea that China now actively disputes. In the event of a major war in the Indo-Pacific, even the largest and most—relative to other JCG vessels—“heavily-armed” JCG patrol ships are unlikely to directly participate in naval operations in the Philippine Sea and around the Japan’s Ryukyu Island Chain, but can nevertheless fulfill roles of non-zero importance in terms of bolstering maritime defences and, no less importantly, and air defences around the Japanese archipelago. JCG vessels are likely to also help facilitate what will likely amount to an all-of-government effort—supported by the privately-owned shipping and aviation sectors—to evacuate civilians from Japan’s Sakishima Islands in the event of a major cross-Taiwan Strait crisis. The JCG may, in time of war, also be stripped of some of its more militarily useful assets, as well as some of its trained personnel, to bolster the Japan Air Self-Defense Force (JASDF) and the Japan Maritime Self-Defense Force (JMSDF).

It is productive take a moment to highlight some of the more militarily useful JCG assets. These include:

• 19 larger JCG patrol vessels that can embark at least one helicopter.

• 10 medium-to-large surface search radar-equipped maritime patrol aircraft.

• 3 MQ-9B SeaGuardian surface search radar-equipped large uncrewed fixed-wing maritime patrol aircraft, which are a variant of the American MQ-9 Reaper.

• ~60 helicopters of various types, most of which exist to provide maritime search and rescue (SAR) services to civilians that will still be required in time of war.

• The JCG’s land-based coastal (surface search) radar network.

In the event of war, the aforementioned JCG assets and associated personnel can be used to bolster JSDF units tasked with:

• Patrolling Japan’s coastline so as to provide early warning of approaching (potentially armed) uncrewed surface vessels (USVs) and (potentially armed) fixed-wing strike drones, and potentially intercept such threats either independently or in concert with the JASDF and/or JMSDF, as well as the Japan Ground Self-Defense Force (JGSDF), which plays an important role in coastal defence.

• Support JMSDF convoying measures to secure merchant ships operating from one Japanese port to another, including vessels used to transport critically important fuels and chemicals from import hubs to industrial facilities across the Japanese archipelago.

• Support JMSDF and JASDF military search and rescue efforts, which will doubtless take place in coordination with American search and rescue efforts.

• Being home to a pool of Japanese persons trained in the operation of small arms and, in some cases, ship-mounted autocannons, the JCG may also be called upon to help bolster wartime Japan’s ground-based short-range air defences to intercept the likes of a Chinese analogue to the Iranian-designed Shahed-136 single-use propeller-driven fixed wing strike drone design that Russia uses against Ukraine under the designation Geran-2.

It bears emphasis that Japanese decision-makers will need to decide—if they have not already done so—when they will pull back JCG vessels and aircraft from “frontline sectors” in the event of a major crisis with China. This includes operations around the Ryukyu Island Chain, given how JCG vessels and aircraft that continue to patrol in this sector are likely to be treated as militarily relevant targets by the PLA, not least when we are discussing JCG vessels—some of which are armed—and aircraft that are equipped with radars that can detect Chinese warships and, in some cases, Chinese aircraft. JCG vessels and aircraft are not equipped with defensive countermeasures and/or defensive armament to have any chance of surviving PLA attacks, a dynamic in which the JCG fleet is notably unlike a specific subset of both the USCG and CCG fleets.

Given the above, JCG operations during a crisis will likely be closely coordinated with the JASDF and JMSDF, and Tokyo may well decide to pull back JCG vessels and aircraft from the Ryukyu Island Chain to the Japanese archipelago as the shadow of war approaches. There is a caveat to be made with respect to an all-of-government effort to evacuate civilians from the Sakishima Islands, but JCG vessels and aircraft have no business being anywhere near the Ryukyu Islands in the event of war with China and are, more to the point, far more useful to Japan’s war effort when located elsewhere.

Cross-Post: Newsletters/sections are primarily categorized by region, and posts can only appear in one section/newsletter at a time. Posts may, however, be relevant to more than one region/section/newsletter.

Commentary-themed posts are intended to broach or highlight a specific issue, not limited to recent and ongoing events. These posts will typically be much shorter and less detailed than analysis-themed posts.

In a recent post, I discussed recent reporting which indicates a previously unpublicized major American role in facilitating Ukraine’s most recent campaign targeting Russia’s energy infrastructure, a campaign that has been far more effective and consequential than previous Ukrainian strike campaigns as a result of what appears to be extensive American intelligence and targeting support.

As I mentioned in the above post, the saga includes an important lesson that is relevant beyond the Russia-Ukraine War: there is more to effective long-range strike capabilities than the mere existence of strike munitions of requisite range. Japan is currently making concerted efforts to develop its own sovereign long-range conventional strike—“counterstrike”—capabilities with the aim of deterring certain Chinese military actions and retaliating if deterrence fails.

Much can be said about this topic, but this post will simply highlight a dynamic that has received comparatively little public discussion to date: will Japan be able to independently acquire the relevant intelligence so as to effectively employ its forthcoming sizeable but nevertheless quite small—given the qualitative and quantitative aspects of China’s air defence capabilities—arsenal of long-range strike munitions against China without American intelligence and targeting support? I think it is a mistake to assume that Tokyo and Washington will have perfect preference alignment in wartime, not least in a situation in which, for example, Tokyo may want to retaliate for a Chinese attack in ways that Washington views to be a waste of finite resources/strike munitions. Japanese decision-makers may, for example, want to independently establish and sustain a “deterrence equation” following a Chinese missile strike against a military target in Japan that inadvertently results in considerable civilian casualties. Japan may, in such a situation, want to strike a target with greater symbolic than military importance.

Absent an independent and sovereign capacity to not only launch strike munitions against China but also acquire the relevant intelligence and other related capabilities, such as weaponeering, Japan may only have an independent/sovereign and effective long-range conventional strike—“counterstrike”—capability in name only. It goes without saying that a Japanese long-range strike capability that is dependent on and, as such, de facto operationally subordinate to, the American military is not a long-range strike capability that Tokyo will be able to primarily hold in reserve—as opposed to regularly employ/consume—to sustain Tokyo’s conception of a wartime deterrence equation vis-a-vis China.

In another recent post, I broached the question of whether the Philippines has become a first strike target for the Chinese military in the way that Japan, or at least American military bases in Japan, have long been widely assumed to be. The military balance in the Western Pacific is evolving in many respects, including what is likely to be—in relative terms—the gradually declining importance of Japan in American military planning and a Japan that will in the near future have a non-zero—but likely qualitatively and quantitatively inadequate—independent capacity through which to independently deter and retaliate against Chinese military attacks on targets in Japanese territory.

All things considered, I think that Japan’s interests are best served if the bulk of Japan’s strike munitions are, in effect, held in reserve over the course of a major conflict and used sparingly against China as required in tit-for-tat strikes. Such a posture for Japan’s strike capabilities is, I think, likely to be the most practical approach to deterring, for example, widespread Chinese strikes against electricity generation and transmission facilities in Japan in a major protracted conflict in the manner that Russia has undertaken against Ukraine, or attacks against Japanese oil refineries and other forms of militarily important national infrastructure more generally. Without a truly independent and sovereign long-range strike capability, which constitutes a lot more than the mere existence of strike munitions of requisite range, Japan’s strike munitions are likely to be de facto operationally subordinate to the American military and, as such, employed in ways that align with the United States’ wartime interests, interests that are only parochial but are also being shaped by the fast-evolving nature of American military strategy in the Western Pacific.

Minimal comment-themed posts are used to introduce data points for use in other posts going forward. Posts of this theme will typically feature minimal analysis and commentary.

In several recent posts, I have covered recent developments in the posture of the China Coast Guard (CCG), a paramilitary organization that is part of the paramilitary People’s Armed Police (PAP) and answers to China’s Central Military Commission (CMC) in the same manner as the People’s Liberation Army (PLA). In recent years, the CCG has established what is best characterized as a fast-expanding armed “high seas fleet” that appears to be intended to not only intimidate and overpower rival claimants in the disputed waters of the South China Sea but also to spearhead a PLAN-backstopped quarantine/blockade type operation in the event of a major crisis over the political fate of Taiwan. The CCG’s fast-expanding “high seas fleet” is also likely to increasingly serve as an adjunct to the People’s Liberation Army Navy (PLAN) in disputed sectors of the East China Sea and regularly operate in the western parts of the Philippine Sea. As a result, the CCG’s “high seas fleet” is likely to become a growing thorn for the Japan Maritime Self-Defense Force (JMSDF) and the Japan Coast Guard (JCG) in times of peace as well as in crises over the political fate of Taiwan.

One of the important questions concerning the future of the CCG is the extent to which its expanding fleet of larger, longer endurance patrol ships, including the vessels that constitute the CCG’s “high seas fleet,” is going to regularly deploy in the disputed waters of the South China Sea. While this is, for the most part, a function of where CCG vessels are homeported, it will also be shaped by the extent to which the CCG is willing and able to rely on smaller and more numerous patrol vessels in its regular standoffs with the Philippines. Relatedly, the scope of the challenge posed by the PLAN to Japan in peacetime will be affected by the extent to which Chinese decision-makers continue to deploy PLAN vessels to serve as a backstop to CCG and Chinese Maritime Militia vessels in the South China Sea.

Another important dynamic that affects Japan is that the CCG is gradually expanding its “overseas” presence in distant waters. The CCG recently completed its tenth North Pacific patrol, and its expanding fleet is increasingly well-positioned to regularly operate in the North Pacific. This may entail the transit of CCG vessels through the Sea of Japan and the passage of both the Tsushima Strait and the La Perouse/Soya Strait. It may also entail the transit of CCG vessels off Japan’s eastern coastline.

Another dynamic to keep in mind is that the CCG is gradually expanding its aviation capabilities. With additional helicopters available, an increasing portion of the CCG’s expanding fleet of flight deck and hangar-equipped vessels will be able to go to sea with an embarked CCG helicopter. The CCG is also deploying vertical take-off and landing (unarmed) fixed-wing uncrewed aircraft to both complement and substitute for CCG helicopters. A CCG vessel in the Sea of Japan or off Japan’s eastern coastline is not, as such, simply a vessel to be monitored but also an aircraft to be monitored. It is worth noting that the CCG has also acquired land-based fixed-wing (unarmed) uncrewed aircraft that can undertake long-distance and long-endurance patrols. CCG uncrewed aircraft patrolling for hours around Japan’s Ryukyu Islands, and CCG uncrewed aircraft patrolling near Tokyo Bay, may become regular undertakings in the not-too-distant future.

This extensions-themed post is an extension of material that has appeared in another newsletter/section and other parts of my website more generally. My newsletters/sections are primarily categorized by region and my posts can only appear in one newsletter/section at a time given how the Substack platform is configured. Extensions-themed posts are intended to highlight content posted in other newsletters/sections that may be highly relevant to readers who are primarily interested in other parts of the world.

In several recent posts, I have discussed how China and the United States are increasingly breaking ahead of all other competitors in a growing number of capability areas and are, in effect, leaving everyone else behind in the dust. As I explained with respect to the six anti-ship munitions that China unveiled at the 3 September 2025 military parade in Beijing, Japan may have considerable resources at its disposal and a world-class technological base, but is nevertheless not immune to the effects of China’s ongoing military modernization and expansion. All things considered, the Japan Maritime Self-Defense Force (JMSDF) is, in important respects, poorly positioned to respond to the growing threat posed by China’s maritime strike capabilities for deep-rooted reasons that mean that this dynamic is unlikely to change any time soon.

While the naval balance is likely to remain a central focus for Japanese decision-makers, I would contend that ongoing advances in China’s air combat capabilities are likely to be far more consequential for Japan’s security going forward. The provisionally and unofficially designated J-36 and J-50, as well as the impressively diverse array of extravagantly developed uncrewed combat aircraft on display at the 3 September 2025 military parade, among other developments in China’s air combat capabilities, portend a future in which Japanese combat aircraft are likely to face increasingly onerous challenges in operating over the East China Sea, including in the airspace above and around Japan’s Ryukyu Islands chain.

Japan’s legacy combat aircraft, namely the F-15J and F-2, which are likely to remain in service into the 2040s, presently remain competitive and credible against the bulk of operational Chinese combat aircraft in 2025 but are likely to be outclassed by a very significant proportion of Chinese combat aircraft over the 2030-2035 timeframe. The Japan Air Self-Defense Force’s (JASDF) steadily expanding fleet of F-35A and F-35B fighter aircraft constitutes a very potent capability set today, but all military systems are wasting assets, Japan’s air bases are no less vulnerable to attacks carried out by the People’s Liberation Army Rocket Force (PLARF) in 2025 than before, and all existing Japanese combat aircraft including the F-35 are heavily reliant on aerial refueling to operate over the East China Sea when deployed at more distant and relatively less exposed Japanese airbases—the effects of geography are inescapable. The limitations of the F-35A—which is hardly an unimpressive fighter aircraft design—for Japan’s specific threat environment and military-geographical context notwithstanding, Japan may well order additional F-35A aircraft to couteract the growing threat posed by Chinese air combat capabilities, to lubricate ties with the brazenly transactional Trump administration, and, perhaps most importantally, to hedge against delays to the tri-nationally developed Global Combat Air Programme (GCAP) that Japan has staked its future air combat capabilities on. GCAP is a collaborative effort between Italy, Japan, and the United Kingdom and amounts to the first time that Japan has staked its future on a successful codevelopment of an expensive and complex military system with a country that is not the United States.

While the pooling of resources is key, given the extraordinary expense of developing a clean-sheet combat aircraft design that significantly expands the technological frontier so as to remain competitive over a service life of around thirty years, Japan’s requirements are unlikely to align very closely with those of Italy and the United Kingdom as a result of Japan’s vastly different military-geographical context and the very different threat that China’s current and prospective air combat capabilities pose relative to those of Russia. There are no known Russian analogues to the Chinese J-36 and J-50 prototypes and the array of uncrewed combat aircraft on display at the recent military parade in Beijing. Russia is, moreover, in no position to both develop an array of new combat aircraft and build said new combat aircraft in very large numbers. The same cannot be said about China, which is currently on track to possess a greatly enhanced set of air combat capabilities over the next decade. Compounding the challenges faced by Japan, the British and Italian governments are working in a very different fiscal context than Japan and reportedly do not share Tokyo’s urgency in aggressively pursuing GCAP development at a pace that is required to allow Tokyo to begin fielding aircraft around 2035.

For decades, Japanese decision-makers had ample time to carefully assess their options, hedge risk, and methodically build up their country’s military capabilities. The intensifying military-technological competition between China and the United States is, however, rapidly undermining the viability of this long-standing “business model,” not least in areas in which Chinese and Japanese modernization cycles do not align. If GCAP is significantly delayed, and reports indicate that the planned first flight has been pushed back to 2027—an ill omen in an area of activity in which further delays can only be expected, the JASDF may come to find itself in a very unfavourable situation over the 2030s. As things stand, the JASDF is, like the JMSDF, heavily reliant on the U.S. military to compensate for its many limitations. If China keeps upping the ante in terms of military-technological development, Japan is likely to find itself ever more reliant on the American military. The stakes for Japan are extremely high—China is on track to be able to credibly execute large-scale air strikes—not just missile strikes—against not only the Ryukyu Islands but also Kyushu and possibly parts of Honshu in the 2030s. It bears emphasis that Nagasaki, which is in western Kyushu, is situated around 800 kilometers from Shanghai, and the entirety of Kyushu falls within 1000 kilometers of Shanghai.

Detering and neutralizing the steadily increasing threat posed by Chinese air combat capabilities over the East China Sea will likely require immense investments in combat aircraft, ground-based air defences, and various supporting capabilities, including but not limited to ground-based radars, airborne early warning and control aircraft (AEW&C), and aerial refuelling aircraft. Japanese decision-makers are being forced to confront the new reality that business as usual is no longer viable, given the frenetic pace at which Chinese air combat capabilities are both improving and expanding and, more generally, to avoid falling very far behind the technological frontier that both China and the United States are increasingly co-establishing. It is possible, even likely, that Japan will once again stake its future air combat capabilities on American military technology in general and close integration with the American military in particular. Specifically, Japan may come to become one of the few foreign operators of the forthcoming American F-47 fighter aircraft, which is understood to be an exceptionally expensive aircraft featuring exquisite and, therefore, very sensitive technology. Unfortunately for Tokyo, publicly available information on developmental timelines suggests that the F-47 may not be fully operational and available in large numbers for the American military, let alone any export customers, until the mid-2030s, by which time China may itself be deploying the likes of the J-36 and J-50 in steadily increasing numbers.

Given the above concerning the American F-47 and reported delays to tri-nationally developed GCAP more generally, a further relative decline in Japanese air combat capabilities vis-a-vis China over the 2030s appears inevitable. While Japanese decision-makers are unlikely to take comfort in the fact that Japan is not the only country lacking any meaningful level of immunity to the externalities of intensifying military-technological competition between China and the United States, the fact remains that we are witnessing a situation in which essentially every country in the Indo-Pacific that is not named China—or the United States—is increasingly being left behind in the dust in what amounts to a two-player game.

The recent military parade in Beijing was used to formally unveil the following anti-ship munitions:

• YJ-15: an air-launched ramjet-powered supersonic anti-ship cruise missile

• YJ-17: a ship- and possibly submarine-launched anti-ship hypersonic boost-glide vehicle, which is to say an offshoot of ballistic missile technology

• YJ-18C: a seemingly subsonic ship/submarine-launched anti-ship cruise missile

• YJ-19: a seemingly submarine-launched scramjet-powered hypersonic boosted high-altitude cruise missile

• YJ-20: a ship- and possibly submarine-launched anti-ship ballistic missile

• YJ-21: an air-launched anti-ship ballistic missile

Of these, only the existence of the YJ-20 and YJ-21—sans designations—was public knowledge prior to the rehearsals for the 3 September parade. No other country is known to have developed, let alone (seemingly) deployed, such a diverse array of qualitatively distinct anti-ship munitions that, in effect, occupy essentially every imaginable niche when it comes to long-range maritime strike capabilities. While this heterogeneous collection of Chinese anti-ship munitions is very impressive, it is important to recognize that all military systems are susceptible to countermeasures of one type or another. All of the aforementioned Chinese anti-ship missiles can be countered with either existing or forthcoming air defence or ballistic missile defence systems. The problem that Japan faces is that most of its surface warships, including most hulls of its latest Mogami-class frigate design, are very limited in terms of the number and types of air defence/ballistic missile defence interceptors that can be carried.

Japan’s surface fleet includes eight large so-called Aegis destroyers of the Kongo-class, Atago-class, and Maya-class. These are very high-end warships that are equipped with either 90 or 96 Mk 41 vertical launch system (VLS) cells each. These eight Japanese destroyers are very well positioned to coevolve with the threat posed by China’s new anti-ship missiles. These warships are, however, Japan’s primary means of extending ballistic missile defence coverage across the sprawling Japanese archipelago. This stems from the fact that these eight destroyers are the only Japanese warships that can use the American RIM-161 (SM-3) exo-atmospheric midcourse ballistic missile defence interceptor. While the Japan Air Self-Defense Force (JASDF) and Japan Ground Self-Defense Force (JGSDF) also operate land-based air and/or ballistic missile defence systems, the JASDF’s Patriot systems and the existing versions of the JGSDF’s Type 03 Chu-SAM cannot substitute for the RIM-161 that are exclusively carried and launched by the JMDSDF’s eight so-called Aegis destroyers. It bears emphasis that the Patriot and Chu-SAM are outclassed by the likes of China’s DF-26 ballistic missile.

Given the threat posed by North Korea’s nuclear-armed ballistic missiles and (primarily) China’s conventionally-armed ballistic missiles, Japan must generally maintain two of these eight so-called Aegis destroyers at sea and fill as many of the 90/96 VLS cells with RIM-161 missiles as possible. Japan had previously planned to build two Aegis ashore systems on land, but has instead decided to build two Aegis system equipped vessels (ASEV) that amount to larger and more capable analogues to its eight existing so-called Aegis destroyers.

Given the above, most of the JMSDF’s so-called Aegis destroyers are likely to go to sea equipped with essentially as many RIM-161 ballistic missile defence interceptors as possible. While one or more of the JMSDF’s eight operational so-called Aegis destroyers may operate as the principal air defence combatant in task groups featuring the rest of the Japanese surface fleet, logistical realities—a subset of the eight-strong fleet of so-called Aegis destroyers is likely to be undergoing maintenance on a given day—mean that the other warships in the Japanese surface fleet will either have to fend for themselves or limit themselves to operating alongside or at least in the vicinity of American so-called Aegis destroyers.

The remaining large warships in the Japanese surface fleet include:

• Seven Asagiri-class vessels, which are best classified as general-purpose frigates. These ageing warships were commissioned between 1988 and 1991 and have a thoroughly outdated air defence suite. The Asagiri-class is, however, being replaced by the new Mogami-class. The Asagiri-class vessels do not incorporate VLS.

• Nine Murasame-class vessels, which are best classified as heavy frigates—these lack—in both qualitative and quantitative terms—the air defence suite required to be counted among destroyers, let alone air warfare destroyers, by contemporary standards. The Murasame-class vessels are equipped with a 16-cell Mk 48 VLS, which can only be used to launch the medium-range RIM-162 Evolved Sea Sparrow Missile (ESSM). While the Murasame-class vessels are also equipped with a 16-cell Mk 41 VLS, each of which can be quad-packed with four RIM-162 missiles, the Mk 41 VLS cells installed on the Murasame-class are used to launch rocket-boosted anti-submarine torpedoes (i.e., anti-submarine missiles). The nine Mursame-class vessels were commissioned between 1996 and 2002. Most vessels of this class are, as such, likely to remain in service into the early 2030s

• Five Takanami-class vessels, which are best classified as heavy frigates—these lack the air defence suite required to be counted among destroyers, let alone air warfare destroyers, by contemporary standards. The Takanami-class vessels are equipped with a 32-cell Mk 41 VLS. As with the Murasame-class, these VLS cells are loaded with RIM-162 medium-range surface-to-air missiles and rocket-boosted anti-submarine torpedoes. The Takanami-class vessels were commissioned between 2003 and 2006 and are likely to remain in service into the 2030s.

• Four Akizuki-class vessels, which straddle the typologies for a heavy frigate and a destroyer. While the Akizuki-class features quite high-end air defence sensors, these are only equipped with a 32-cell Mk 41 VLS that is loaded with RIM-162 medium-range surface-to-air missiles and rocket-boosted anti-submarine torpedoes. The Akizuki-class vessels were commissioned between 2012 and 2014 and are likely to remain in service into the 2040s.

• Two Asahi-class vessels, which amount to evolved Akizuki-class hulls. These are similarly equipped with a 32-cell Mk 41 VLS that is loaded with RIM-162 medium-range surface-to-air missiles and rocket-boosted anti-submarine torpedoes. The two Asahi-class vessels were commissioned in 2018 and 2019, respectively, and may well remain in service into the early 2050s.

The Japanese surface fleet also includes the country’s latest warship design, the Mogami-class, which I will return to later in this post. It is important to first recognize that the Asagiri-class, Murasame-class, Takanami-class, Akizuki-class, and Asahi-class ships—a total of 27 warships that coexist alongside just eight much larger and far better equipped so-called Aegis destroyers—are incapable of independently intercepting several of the new Chinese anti-ship munitions, given that the American RIM-162 medium-range surface-to-air missile is incapable of intercepting ballistic missiles and boost-glide vehicles such as the YJ-17, YJ-20, and YJ-21. The RIM-162 is also likely to be outclassed by the YJ-19 scramjet-powered hypersonic anti-ship cruise missile.

It bears emphasis that the current composition of the Japanese surface fleet and its limitations in terms of air defence capabilities are no accident. For decades, the JMSDF has placed a heavy emphasis on its anti-submarine warfare capabilities. This largely reflected the modest threat posed by the surface fleets of China and North Korea, and to a far more limited extent, even the Soviet Union and later Russia. Submarines were, however, a major threat, and anti-submarine warfare capabilities, which were and remain a capability area in which large numbers of geographically dispersed ships are required, amounted to an area in which Japan could offer the greatest value-add to its treaty ally, the United States, which always welcomed anti-submarine warfare-optimized allied warships that could bolster its own fleet.

The problem that Japan currently faces is that China’s maritime strike capabilities have evolved considerably and are now missile-centric and require very high-end naval air defence capabilities, and in some cases, naval ballistic missile defence capabilities, to counter. As I explained earlier in this post, the six recently unveiled Chinese anti-ship munitions occupy essentially every imaginable niche when it comes to long-range maritime strike capabilities. Countering these is a big enough challenge for the United States Navy; it is far beyond the reach of the likes of Southeast Asian, and is already straining Japan’s naval capabilities. It also bears emphasis that while the threat posed by Chinese submarines to Japan has not disappeared, it is changing. In part, this reflects the increasing sophistication of the latest in Chinese submarine technology. It is, however, also reflective of how China’s submarines are increasingly being employed as submerged and, as such, concealed, forward-deployed launchers for long-range Chinese anti-ship munitions. While little is known about the specifications of China’s recently unveiled anti-ship munitions, it is possible that both the YJ-18C and YJ-19 can be launched from standard 533 mm diameter submarine tubes. Going forward, larger anti-ship munitions such as the YJ-17 and YJ-20 may also be carried from new Chinese submarine designs that feature some form of VLS.

As a result of its maritime geography and the chokehold that Japan can exert on Chinese submarines and surface ships alike through the passages between Japan’s Ryukyu Island Chain, the JMSDF is unlikely to abandon its longstanding emphasis on anti-submarine warfare capabilities any time soon. As a result of the ever-expanding threat posed by Chinese and North Korean ballistic missiles, the JMSDF is also unlikely to abandon allocating immense resources toward sustaining a fairly small but critically important ballistic missile defence capable fleet of so-called Aegis destroyers. As things stand, the JMSDF is largely unprepared for and, for the foreseeable future, has limited scope for countering China’s fast-evolving maritime strike capabilities. The limited air defence capabilities of Japan’s latest Mogami-class frigates are a case in point.

In May 2025, the JMSDF commissioned its seventh Mogami-class frigate, the JS Niyodo. The first of the total of twelve—originally twenty-two—planned Mogami-class frigates was commissioned in 2022, and the commissioning of the JS Niyodo should have been a routine matter. There was, however, something different and notable about the JS Niyodo—it is the first Mogami-class frigate to have been built and commissioned with VLS, namely a 16-cell Mk 41 VLS. However impressive and internationally competitive Japan’s Mogami-class frigates are in essentially every other respect, the fact remains that Japan built and commissioned six new ~5500 tonnes full displacement frigates in the early 2020s that were limited to an air defence suite that included just one 127 mm naval gun and eleven radar-directed passive radio homing/imaging infrared very short-range RIM-116 surface-to-air missiles. The first six Mogami-class frigates are, as such, essentially defenceless when targeted by the likes of the Chinese YJ-17, YJ-19, YJ-20, and YJ-21, and are more generally vulnerable to saturation attacks involving the likes of the YJ-15 and YJ-18C as well as other far less sophisticated anti-ship cruise missiles. It bears emphasis that the Mogami-class were built in a fitted-for-but-not-with configuration that could accommodate a 16-cell Mk 41 VLS. The VLS cells found on the seventh Mogami-class hull onward—which will be fitted to the first six Mogami-class hulls going forward—are notably limited to carrying rocket-boosted anti-submarine torpedoes for the time being.

Japan originally planned to build twenty-two Mogami-class frigates before reducing the total to twelve. The JMSDF will instead acquire twelve New FFM frigates, which are larger and better-equipped Mogami-class derivatives. Japan, it seems, recognized—belatedly—that it was buying too many warships of inadequate capability and adjusted course accordingly. While the New FFM frigates will reportedly include only 32-cell Mk 41 VLS, these will reportedly be loaded with the new Japanese Type 23 surface-to-air missile, which will amount to a major upgrade over the RIM-162 ESSM. Notably, the Type 23 surface-to-air missile is not understood to be capable of intercepting ballistic missiles. Leaving aside the RIM-161 (SM-3), which the New FFM class cannot in any event support given the limitations of its radars, there is no indication that Japan’s New FFM frigates are set to use the American RIM-174 (SM-6) or RIM-156 (SM-2) long-range surface-to-air missiles. Even if the New FFM frigates can accommodate the RIM-174, RIM-156 and similar long-range surface-to-air missiles more generally, and however sophisticated the Japanese Type 23 SAM may be, each New FFM frigate will only have thirty-two Mk 41 VLS cells, several of which are likely to be loaded with rocket-boosted anti-submarine rockets at any given time. Simply stated, even the New FFM has questionable survivability given the increasing threat posed by China’s maritime strike capabilities.

As I explained in the context of Southeast Asia, China’s recently unveiled anti-ship munitions leave most of China’s neighbours unable to keep up and deploy credible naval forces for the foreseeable future. By virtue of its considerable resources and world-class technological base, Japan is far better positioned to keep up, but it is nevertheless not immune to the effects of China’s ongoing military modernization and expansion. Moreover, there is a case to be made that the JMSDF is not only unprepared to respond to China’s increasingly formidable maritime strike capabilities but also has limited scope to do so for the foreseeable future, given the current composition of the Japanese surface fleet and planned naval construction. Japan’s eight—ten by the end of the decade—so-called Aegis destroyers cannot be everywhere at once and are central to Japan’s ability to defend its territory from Chinese and North Korean ballistic missiles. These destroyers are also set to employ RGM-109 Tomahawk land-attack cruise missiles, a dynamic that will further strain Japan’s ability to counter China’s new anti-ship munitions. As things stand, the JMSDF will likely have to deploy its warships in a very cautious manner in time of war and will likely have to, in effect, cling to the U.S. Navy, which is the only navy in any position to counter the entire array of new anti-ship munitions that China has developed and seemingly deployed.

This post is an extension of material that has appeared in another newsletter/section and other parts of my website more generally. While my newsletters/sections are primarily categorized by region—you can either subscribe to specific newsletters/sections or subscribe to the entire website/all of my writings—many posts can be readily placed in multiple newsletters/sections—but only appear in one newsletter/section given how the Substack platform is configured—and may be highly relevant to readers who are primarily interested in other parts of the world. Posts dealing with ongoing conflicts or advances in military technology, for example, may highlight developments and dynamics that may be be of consequence to other countries. Similarly, posts that deal with the military capabilities of one country may be relevant to readers who are primarily interested in the military capabilities of other countries. My Extensions themed posts will be used to highlight content that I think subscribers of other newsletters/sections may find interesting. I hope that my Extensions themed posts help rationalize my peculiar comparativist analytical approach, one that results in my website covering a very wide range of military-related topics and much of the world.

In a recent post, I addressed some of the military implications of the increasing availability of Starlink’s low Earth orbit (LEO) satellite communication (SATCOM) service across the Middle East. Commercial LEO SATCOM providers like Starlink offer low-latency and high-bandwidth satellite internet service to users located in essentially any part of the coverage area, which is determined not by technology but by the ability of individual governments to regulate the use of radio frequencies on and above their territory under the provisions of the International Telecommunications Union (ITU). While LEO SATCOM can be used to access the internet, it can also be used as a datalink for military purposes. LEO SATCOM can be used to:

• Remotely pilot uncrewed systems, including uncrewed aircraft.

• Access the real-time feed of the sensors carried by uncrewed systems.

• Provide uncrewed systems with accurate and reliable positioning data as an alternative to Global Positioning System (GPS) and other global navigation satellite systems (GNSS) more generally.

• Remotely activate pre-positioned munitions and other forms of military equipment more generally.

• Support the operations of adversary special forces, intelligence operators, and local collaborators more generally.

While the two countries that were the focus of my recent post, Saudi Arabia and the United Arab Emirates, have not yet granted Starlink approval to offer commercial satellite internet service in and above their territory, Starlink is readily available in Japan. Although LEO SATCOM has clear-cut benefits for Japan’s economy and the lives of the country’s inhabitants, it also has the inherent potential of substantially enhancing Chinese and North Korean military capabilities. While China has its own (non-LEO, at this time) SATCOM capabilities, it can nevertheless make use of readily available Starlink’s low-latency and high-bandwidth satellite internet service to enhance both its military and intelligence capabilities. For North Korea and other countries that (A) do not have their own communication satellites and (B) have very limited access to the communication satellites of other countries and commercial satellite internet services more generally, readily available satellite internet from Starlink and, going forward, other commercial LEO SATCOM providers, will enable a very significant enhancement of the country’s military and intelligence capabilities.

To be clear, the potential threat posed by the availability of Starlink and LEO SATCOM more generally to Japan should not be exaggerated and should be viewed in its proper context. As with most areas of government policy, Japanese decision-makers faced trade-offs and appear to have ultimately decided that the benefits of commercially available low-latency and high-bandwidth satellite internet to Japan outweigh the costs and risks to the country. Even so, observers must be mindful that these costs and risks are of the non-zero variety. As with other countries that have approved Starlink’s satellite internet service—and even those that have not in times of war—LEO SATCOM amplifies the longstanding threats posed by adversary strike munitions, special forces, and intelligence agents.

If you find this topic interesting, consider reading my post dealing with the increasing availability of Starlink’s satellite internet service across the Middle East: