Japan's railgun ready to zap Chinese hypersonic missiles

Asia Times

22-04-2025

Japan's ship-mounted railgun offers a cost-effective and rapid response to potential missile saturation threats by utilizing electromagnetic energy to launch projectiles at hypersonic velocities.
This month, Naval News reported that the Japan Maritime Self-Defense Force (JMSDF) disclosed the deployment of its advanced railgun aboard the test ship JS Asuka, marking a significant milestone in electromagnetic weaponry.
Developed by Japan's Ground Systems Research Center (GSRC) under the Ministry of Defense's Acquisition, Technology & Logistics Agency (ATLA), railgun research began in 2016 and achieved its first shipboard firing test in October 2023.
The weapon system demonstrates enhanced muzzle velocity, reaching 2,000 meters per second, and stability for firing up to 120 rounds, overcoming challenges of rail erosion and projectile flight stability. Current research aims to transition to a complete 'gun system,' integrating continuous firing, flight stability improvements and a tailored fire control system.
Japan's railgun could bolster naval missile defenses, provide new options for land-based artillery such as counter-battery fire and coastal strikes, and theoretically contribute to intercepting specific high-speed missile threats. However, a miniaturized power supply remains pivotal for practical deployment.
Japan also collaborates with France and Germany's Research Institute of Saint-Louis to advance railgun technologies, reflecting international scientific cooperation. This breakthrough positions Japan's railgun as a cornerstone for future defense systems, promising technological and operational maturity through FY 2026.
Unlike the US Navy, which halted its railgun project in July 2021 because of significant power, overheating and rail wear challenges, Japan continues to pursue the technology to address the possible shortcomings of missile-based defense and strike capabilities.
Missiles offer powerful long-range strike options but are extremely expensive and limited by shipboard magazine capacity. US Navy destroyers and cruisers carry only 96–122 missiles in their Vertical Launch System (VLS) cells.
During operations against Houthi rebel forces from 2023 to 2025, the US expended hundreds of difficult-to-replace, multi-million-dollar missiles to down relatively cheap drones and ballistic missiles, highlighting an unsustainable cost curve and dangerously shallow magazines.
Japan faces a similar problem. In December 2022, Kyodo News reported that Japan had only 60% of the interceptor missile stockpiles deemed necessary for national defense.
Underscoring the missile threat, Newsweek reported in March 2025 that China has significantly increased the number of its missiles capable of hitting Japan.
According to the report, new bases in China's Jilin and Shandong provinces house three types of missiles—the DF-17 medium-range ballistic missile and the CJ-10 and CJ-100 ground-launched cruise missiles (GLCM), which can penetrate Japan's existing missile defenses.
Beyond limited magazine depth, the inability to reload VLS cells at sea presents another major constraint.
In a March 2024 article for the Georgetown Studies Review, Tyler Koteskey mentions that despite their effectiveness, US Mk41 VLS must be reloaded in port. Koteskey notes that early attempts to install foldable cranes on US vessels failed, given the challenges of loading heavy canisters of munitions in rough seas.
He adds that, depending on the availability of such facilities, returning to a port capable of reloading VLS can take weeks. He stresses that large-scale missile salvo attacks could rapidly deplete US VLS magazines in a high-end combat scenario.
Japan is already building large Aegis System Equipped Vessels (ASEVs) to compensate for magazine limitations. However, concentrating so much capability on a few high-value ships makes them prime targets for North Korea and China attacks.
Railguns may offer a critical solution to these missile defense bottlenecks. In a December 2011 Proceedings article, Maxwell Cooper notes that railguns can deliver many rounds at distances comparable to most missiles with the same lethality and accuracy, while at lower costs and greater quantities.
Cooper explains that railguns fire projectiles at hypersonic speeds, with the round itself using its massive kinetic energy for destructive effects—no explosive filling is required. He also suggests that rounds could be equipped with GPS units for greater accuracy and that the absence of explosive propellant frees up some magazine space.
However, while railgun rounds are smaller and cheaper than missiles, they still require substantial onboard power and projectile storage.
Further, Cooper mentions that the lack of a capable multi-mission gun has forced US Navy commanders to use expensive, limited, high-end missiles for all types of targets, creating a gap in the ability to economically engage lower-end threats such as patrol boats, undefended coastal targets and basic ballistic missiles, which would otherwise be engaged with low-cost gun rounds.
Railguns could also provide an economical means to counter saturation missile attacks. An April 2022 US Congressional Research Service (CRS) report mentions that it takes 300 seconds to detect a missile launch signature, track the projectile, and calculate a vector for defensive projectiles.
The report states that an 11-kilogram railgun projectile can disperse more than 500 three-gram tungsten impactors capable of destroying incoming missiles through sheer kinetic energy.
While railguns offer promise, Japan still faces critical questions: Can Japan integrate and scale the technology fast enough to counter China's growing missile arsenal? And, can it avoid concentrating too much capability on a few vulnerable ships?