Defense Ministry to Conduct Railgun Prototype Firing Test on MSDF Ship; Eyed as Hypersonic Weapon Countermeasure

The Yomiuri Shimbun

14:20 JST, May 12, 2025

The Defense Ministry plans to test a railgun prototype, a weapon that utilizes electromagnetic force instead of gunpowder to fire projectiles at very high speeds, on an experimental ship off the coast of Japan in the near future, The Yomiuri Shimbun has learned.

Railguns are cutting-edge weapons that are considered a potential countermeasure against hypersonic weapons, which China and North Korea are developing. The defense ministry is eyeing the deployment of railguns with a view to installing them on Aegis-equipped ships.

When an electric current is passed through a pair of parallel rails, a magnetic field is generated, which causes the metal projectile inside the railgun to be fired. It can generate much higher speeds and cover much further distances than conventional artillery. It is also considered advantageous in terms of the safety of JSDF personnel, as storing ammunition is easy because it does not use gunpowder.

In addition to attacks on vessels, aircraft and drones, railguns have the potential to be used to intercept hypersonic weapons, which travel at least five times the speed of sound along irregular trajectories at low altitude. Railguns are considered to be a game changer that can transform the balance of power.

The ministry started research on railguns in fiscal 2016 and an offshore firing test was conducted using a small prototype on the Maritime Self Defense Forces’ experimental ship JS Asuka in summer 2023.

The upcoming test will use a prototype which is the expected size of those to be used in actual warfare – about six meters long and weighing about eight tons. This is the first offshore test using a near full-scale prototype, and the ministry will check such things as whether it can accurately reach its target.

The ministry concluded the Terms of Reference for cooperation on railgun technologies with France, Germany and a research institute. Hoping to have railguns enter practical use, the ministry has also dispatched its technical officers to the U.S. military, which has suspended its railgun development, in order to utilize its experimental data.

Railguns are being eyed for deployment on Aegis-equipped ships and new-model destroyers. However, some issues still need to be solved, such as rails being damaged over time by the projectiles, making continuous firing difficult and reducing the muzzle velocity.

China has also accelerated its railgun development. According to Hong Kong-based newspaper South China Morning Post, China’s Naval University of Engineering revealed that it had succeeded in firing off 120 rounds in a research paper published in November 2023. The newspaper said that it would put “China ahead of the pack, globally.”