For decades, Japan has put self-imposed restraints on its defense ambitions. Showcasing new, ground-breaking military tech was a serious taboo in a country where unhinged militarism led to its catastrophic defeat in the Second World War.
However, at the ongoing DSEI Japan exhibition, Tokyo has shed that shyness by flaunting its cutting-edge railgun. A weapon straight from sci-fi novels that was considered impractical and technologically unattainable until a few years back, even by the US.
The event near Tokyo, Japan’s biggest defense expo so far, opened on May 21 and attracted 471 firms from 33 countries, including 169 from Japan.
Tokyo is showcasing high-powered lasers, missiles, drones, trainer jets, and a host of new defense platforms at the exhibition. It marked what Defense Minister Gen Nakatani termed the pacifist nation’s deepening push for overseas defense cooperation and weapons exports.
However, at the expo, one particular kiosk is generating all the buzz. Here, visitors can get a close look at the futuristic “railgun” that its makers believe can even shoot down hypersonic missiles.
While the Japanese Navy test-fired the weapon for the first time last year and Tokyo released a few images in April, this is perhaps the first public display of the gun.
Japan Displays Futuristic ‘Railgun’ At Defense Expo That Makers Believe Could Shoot Down Hypersonic Missiles pic.twitter.com/T6I8uouLML
— EurAsian Times (@THEEURASIATIMES) May 22, 2025
Railguns were theorized in the 1920s, over 100 years ago, and many countries, including China, France, Germany, and India, have tried building one.
The US, the most advanced defense-industrial power on earth, famously abandoned its plans for building railguns in 2021 after encountering multiple tech hurdles. However, Tokyo succeeded, where Washington failed.
To better appreciate the technological bottlenecks one must overcome to build railguns, one needs to understand the deceptively simple yet complex science behind it.
How Railguns Work
Notwithstanding the over one-hundred-year history of efforts to build railguns, the basic science behind it is quite simple.
Railguns use electricity and magnetism, not gunpowder, to launch projectiles at hypersonic velocity.
A railgun consists of two parallel metal rails connected to a power source. These rails are placed close together, with a conductive projectile (often a metal ball) between them. When the railgun is activated, a massive electric current flows through one rail, across the projectile, and back through the other rail, creating a complete circuit.
This huge current generates a powerful magnetic field around the rails. According to a principle called the Lorentz force, when electricity flows through a conductor (the projectile) in a magnetic field, it creates a force that pushes the projectile forward.
This force accelerates the projectile to hypersonic velocities, often exceeding Mach 5 or more than five times the speed of sound.
In other words, instead of gunpowder and explosives, a railgun uses an electromagnetic field to push the metal ball forward to its target at hypersonic speed.
The projectile’s incredibly high speed means it gathers enough kinetic energy to destroy any potential target. The projectile could be any metal ball without any explosives. The projectile will destroy the target through its sheer speed, think of a meteor hitting the Earth.
Put simply, a railgun converts electromagnetic energy into kinetic energy and uses that kinetic energy to destroy a target, such as a ship or a hypersonic ballistic missile.
It sounds simple, but its deceptive simplicity hides many technological hurdles. These hurdles ensured that railguns remained in the realm of sci-fi for the whole of the 20th century, even when theoretical models were developed in the 1920s.
The Tech Hurdles In Railguns
The first bottleneck was the immense electrical power a railgun requires to work. Even a small railgun could consume electrical power equivalent to 10,000 homes. Generating and storing that amount of electricity was a challenge.
The second hurdle was that this high amount of force would wear out the rails quickly. The high electrical current and magnetic stress also frequently damaged the parallel conductors. The scientists needed to develop rails that could handle that much force consistently.
A third challenge was to guide the metal ball travelling at hypersonic speeds. A metal ball travelling at Mach 5 or Mach 7 cannot receive Satellite Navigation (SatNav), making it an unguided shell.
The Failed US ‘Dream Shell’ Project
These challenges meant the US Navy abandoned its ‘dream shell’ project in 2021 after years of research and draining over US$500 million. It redirected the funding towards hypersonic missiles, directed energy weapons (DEW), and electronic warfare (EW) systems.
Military and naval warfare analyst Bryan Clark from the Hudson Institute said the US spent US$500 million on the program over a decade. The biggest drawback was the system’s limited range – 110 miles (177 km) – clocked during testing.
“A Navy vessel could not employ the gun without putting itself within range of a barrage of enemy missiles. And its usefulness for missile defense was also limited by range and rate of fire,” Clark said.
The US Navy first planned to deploy the electromagnetic railgun system on the USS Lyndon B. Johnson, a Zumwalt-class warship. That plan was later canceled.
The Chinese, Japanese Breakthrough
Despite the US abandoning its ‘Dream Shell’ project in 2021, China and Japan continued the work on Railguns.
In February last year, China claimed a breakthrough.
A team led by Feng Junhong, with the National Key Laboratory of Electromagnetic Energy at the Naval University of Engineering, published a paper in the Journal of the Naval University of Engineering in November.
The team claimed that its research resulted in the metal shell fired from a railgun receiving stable signals from the BeiDou satellite navigation system. It consistently adjusted its flight path, maintaining an error of less than 15 meters (49 feet) “until it hits its target.”
“Achieving such high accuracy at such high speeds is not easy, as the shell can travel 2,500 meters (8,200 feet) per second,” the report added.
The Chinese scientists developed a unique “antenna” that can resist intense electromagnetic radiation and receive clear signals from the BeiDou constellation’s military frequency band.
However, in the absence of practical demonstration, many military analysts took the Chinese claims with a grain of salt. Chinese naval scientists repeated these claims in January this year.
Japan started working on the railgun project in 2016 and has invested US$300 million over the past three years. A prototype of the weapon is already undergoing trials aboard a Maritime Self-Defense Force test vessel.
However, Tokyo’s public unveiling of the railgun at the ongoing DSEI Japan exhibition shows that it is confident in its technology and product reliability.
- Sumit Ahlawat has over a decade of experience in news media. He has worked with Press Trust of India, Times Now, Zee News, Economic Times, and Microsoft News. He holds a Master’s Degree in International Media and Modern History from the University of Sheffield, UK.
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