The Japan Maritime Self-Defense Force (JMSDF) has officially unveiled its new electromagnetic railgun, installed on the turret of the test ship JS Asuka. The first images of the system were released during a visit to the ship by Vice Admiral Omachi Katsushi on April 9. The weapon was developed by the Acquisition, Technology & Logistics Agency (ATLA), which operates under the Japanese Ministry of Defense and has been working on the system since 2010 with the goal of integrating it into naval vessels and potentially coastal installations.
It is worth recalling that the ship hosting the new electromagnetic railgun—commissioned in 1995 and displacing around 6,200 tons—is part of the Fleet Research and Development Command (FRDC). As its name suggests, this division plays a key role in the research, development, and testing of new technologies that the JMSDF may incorporate to enhance its capabilities. This context is relevant since, in recent weeks, local observers had already published images of the JS Asuka docked at port with a new, unfamiliar turret—now confirmed to be the new weapon system.
As background, it should also be noted that as early as 2023, ATLA had announced it had successfully tested a prototype of the weapon from an unspecified naval platform, showcasing the progress made and positioning Japan as a pioneer in this type of armament. At the time, however, the railgun was seen in a temporary mounting rather than the fully integrated turret that has now been publicly shown aboard JS Asuka.
While specific technical details of this latest version remain undisclosed, some insights can be gleaned from prior testing. According to ATLA, the Japanese electromagnetic railgun can fire 40 mm projectiles at speeds of approximately 2,230 meters per second, equivalent to about Mach 6.5, using around 5 megajoules of energy per shot. Specialized media have reported that each gun is expected to have a service life of roughly 120 rounds without requiring recharging. This latest version may also include improvements enabling it to operate with reduced energy consumption.
During the early stages of development, generating enough power onboard a ship to operate the gun was one of the major obstacles, alongside the need for an effective cooling system capable of handling the heat produced during rapid-fire operations. Additionally, the large size of the railgun and its turret—mainly due to the batteries required to power it—raises questions about the feasibility of installing it on current JMSDF vessels. In the case of JS Asuka, installation was only possible on the aft flight deck, which normally accommodates helicopters and/or drones. These technical challenges, along with high costs, were key reasons behind the cancellation of the U.S. railgun program earlier this decade.
Finally, it is worth noting that the advancement of this new electromagnetic railgun will not only benefit the JMSDF, but also its counterparts in Germany and France. As reported last May, the three countries reached a cooperation agreement titled the “Implementation Guidelines for Railgun Technology Cooperation,” which paves the way for joint efforts to accelerate the development of such weapons. For Germany and France, this is represented by the 25 mm RAFIRA system currently being developed by the Saint-Louis Research Institute (ISL).
Header image: @JMSDF_SDF_ENG on X
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