Japan’s railgun locked and loaded to kill China’s hypersonics

By punching real holes in a target ship with a weapon the US shelved, Japan’s prototype railgun is turning hypersonic gunfire into a cheap, hard-to-stop answer to China’s missile and drone swarms – and hinting at a gun-driven comeback in surface warfare.

This month, The War Zone (TWZ) reported that Japan’s Acquisition Technology & Logistics Agency (ATLA) has disclosed the first evidence of damage inflicted by its prototype electromagnetic railgun on a target vessel, underscoring its determination to advance a capability the US Navy abandoned in 2022.

The test, conducted in summer 2025 aboard the Japan Maritime Self-Defense Force’s (JMSDF) 6,200-ton test ship JS Asuka, involved firing fin-stabilized, dart-shaped projectiles at a tug-like vessel under tow. Images released at ATLA’s annual Defense Technology Symposium showed multiple impact points, confirming stable flight and effective strikes.

Operators remotely aimed the weapon using cameras and radar, while drones captured footage. The railgun, an evolution of designs ATLA has pursued since the mid-2010s, achieved projectile velocities of around 2,300 meters per second and demonstrated barrel life exceeding 200 rounds, a significant advance over earlier benchmarks.

The installation required four shipping containers of support systems to meet power and cooling demands, highlighting persistent engineering challenges. Officials said the trial provided critical data on integration and operation aboard naval platforms, with implications for future anti-air and anti-surface roles, particularly against hypersonic threats.

Japan’s railgun program is best understood as a strategic solution to three converging pressures – hypersonic threats, magazine-depth limits and the unsustainable economics of missile defense.

China’s expanding missile force poses a clear threat to Japan. The US Department of Defense’s (DoD) 2024 China Military Power Report notes that China’s DF-17 hypersonic missile is meant to bypass missile defenses and hit US bases and forces in the Western Pacific, including those stationed on the Japanese island of Okinawa.

The report also mentions China has around 1,300 medium-range ballistic missiles (MRBMs) and 400 ground-launched cruise missiles (GLCMs) with 150 launchers, with that force capable of hitting any point in Japan.

Beyond the missile threat, Stacey Pettyjohn and Molly Campbell mention in a September 2025 Center for a New American Security (CNAS) report that Japan’s frontline islands in a Taiwan contingency – particularly Yonaguni – are vulnerable to Chinese drone swarms.

Pettyjohn and Campbell point out that the scale of Chinese drone swarm attacks would most likely outstrip US interceptor missiles and ammunition stocks.

Those threats have also exposed fundamental weaknesses in Japan’s Aegis–Patriot missile shield, where interceptor scarcity, long production lead times and exorbitant per-shot costs erode missile defense capabilities.

Railguns, by contrast, offer a radically different cost-exchange ratio, transforming magazine capacity from a limited missile count into essentially a function of electrical power generation and onboard storage.

The technology may give Japan a scalable tool for countering everything from select missile threats to drone swarms – roles currently forcing commanders to expend multimillion-dollar missiles on cheap targets.

Beyond missile and drone defense, railguns could bring about a renaissance of naval guns for ship-to-ship engagements, which anti-ship missiles have long superseded.

For context, the US Mark 45 127-millimeter gun has a range of 24 kilometers with conventional ammunition, with a 600-round magazine for destroyers and 1,200 rounds for cruisers, with a 16-20 rounds per minute rate of fire.

Furthermore, the US Advanced Gun System (AGS) previously mounted on the Zumwalt-class destroyers had a range of 137 kilometers and was optimized for shore bombardment, but the exorbitant cost of US$800,000-$1 million per round forced its cancellation and the rearmament of the Zumwalt-class with hypersonic missiles.

A railgun could simultaneously address range and cost issues surrounding conventional naval guns. According to an April 2022 report by the US Congressional Research Service (CRS), a $85,000 hypervelocity projectile fired from a railgun could reach a velocity of Mach 5+ with a range of 185 kilometers. For comparison, a US Harpoon Block II anti-ship missile costs $1.4 million per round, with a range of 124 kilometers.

In practice, a peer-to-peer ship-to-ship engagement will center primarily on anti-ship missiles, unless a new technology changes that paradigm – railguns offer missile-level range and lethality, while giving the cost advantage of naval guns.

Railguns offer hypersonic muzzle velocity, drastically reducing enemy reaction time with a near-instantaneous hit. The lack of a huge firing signature, such as a heat plume or radar returns, could make railgun shots hard to detect compared to missiles.

Furthermore, kinetic projectiles may prove to be devastating against modern warships, which may not be built to withstand railgun-fired blows. The advent of anti-ship missiles has made thick steel naval armor obsolete, with contemporary ship defenses built around layered soft and hard-kill systems such as electronic warfare, chaff and flares, and close-in weapons systems (CIWS) to defeat incoming missiles.

In the case of the US Arleigh Burke-class destroyers, the class is unarmored aside from vital areas that are protected by two spaced layers of steel and Kevlar armor – hardly armor compared to the 307-millimeter armored belts of the World War II Iowa-class battleships.

Still, those changes mark a paradigm shift in ship defense – the best defense is not to get hit in the first place – as opposed to having the capability to withstand a hit. But as a result, it may take only one hit to put a modern warship out of action.

A potential renaissance of naval gunnery brought about by railguns could bring about a rethink of warship design, which may have to balance survivability against speed and other requirements.

While adding armor may significantly increase survivability, the added weight could negatively impact speed and compete with weight requirements for sensors and weapons. Additionally, armor may not guarantee continued combat effectiveness after such a hit – it is unclear whether the sensitive and interconnected electronic systems of a modern warship can withstand the effects of a hypersonic projectile impact.

Still, railguns remain an experimental technology, having yet to overcome technical challenges such as barrel life, space, cooling and power requirements. Should these challenges be addressed, namely through more efficient and smaller cooling and power generation technology, future warship designs could incorporate both railgun technology and armor protection, without compromising on speed and space.

While the US may have foregone ship-based railguns for good, as recent concept designs of its upcoming DDG(X) destroyer show its gun swapped out for missile launchers, Japan’s Aegis System Equipped Vessels (ASEVs) may be armed with railguns, possibly having the size to accommodate such a system.

Japan’s railgun tests hint at a future where hypersonic, low-signature kinetic strikes may end the long-standing missile monopoly in naval warfare, forcing adversaries to reckon with a cheaper, faster and harder-to-stop alternative.

If Japan can solve the remaining power and barrel-life hurdles, it won’t just field a new weapon—it may reorient surface combat back to the naval guns that modern warships are not built to survive.