Japan has fired the first ship-mounted railgun at sea, a hypersonic shot that could rewrite the balance between guns and missiles in naval warfare.

This month, Naval News reported that Japan's Ministry of Defense (MoD), through its Acquisition, Technology & Logistics Agency (ATLA), announced the country's first successful live firing of a ship-mounted electromagnetic railgun against a target vessel at sea, representing a potential significant turning point in Tokyo's advanced weapons development.

The test aboard the Japan Maritime Self-Defense Force's (JMSDF) test ship Asuka involved long-range firings and precision targeting, with ATLA releasing visual documentation via its official social media platforms.

The railgun, which uses electrical energy to launch hypervelocity projectiles—reaching speeds of nearly Mach 7—was developed to counter emerging hypersonic threats from China, North Korea and Russia.

This breakthrough follows ATLA's earlier sea-based railgun test in October 2023 and the public exhibition of a half-scale model at DSEI Japan 2025 in Chiba Prefecture. While the technology promises rapid-fire capability and lower operational expenses compared to conventional interceptor missiles, its deployment faces challenges, notably the need for high-capacity power systems and miniaturization for integration into naval systems.

Japan's strategic focus on railguns, high-power microwaves and laser-based systems reflects its intent to bolster missile defense capabilities amid rising regional tensions and China's missile build-up. Further technical details are expected to be disclosed at the ATLA Technological Symposium 2025, scheduled for November in Tokyo.

Testing a railgun against a surface target could lead to a revival of naval guns, which missiles have superseded as the primary weapon in naval warfare. Railguns for surface warfare could address a longstanding overreliance on expensive anti-ship and cruise missiles to target low-end vessels or shore-based installations, thereby reserving these assets for major surface combatants or critical targets deep in enemy territory.