Japan's Navy Is Poorly Positioned To Respond To Growing Threat Posed By New Chinese Anti-Ship Munitions
🇨🇳 🇯🇵 Analysis
The major military parade held in Beijing on 3 September 2025 served as an opportunity for China to unveil no fewer than six qualitatively distinct anti-ship munitions. As I explained in a recent post, the unveiling and presumed operational status of such a diverse array of anti-ship munitions is driving a transformation of the regional naval balance in a manner that leaves most of China’s neighbours unable to keep up and deploy credible naval forces for the foreseeable future. Japan possess one of the world’s largest and most sophisticated naval fleets, a fleet that is designed to operate closely alongside and complement the United States Navy. Japan’s military industry has for decades been at the forefront of many areas of naval technology. And yet, Japan is not immune to the effects of China’s ongoing military modernization and expansion. The recently unveiled Chinese anti-ship munitions constitute a major challenge that the Japan Maritime Self-Defense Force (JMSDF) not only appears to be largely unprepared for, but has a limited scope for countering China’s fast-evolving maritime strike capabilities for the foreseeable future, given the current composition of the Japanese surface fleet.
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.