Japan’s Railgun Performs First Test Firing At Sea

Japan’s long in development medium-caliber electromagnetic railgun could offer a huge boost in point defense capabilities.

byOliver Parken|
Test firing of Japanese railgun
ATLA via Twitter/X


Japan says it successfully test fired its medium-caliber maritime electromagnetic railgun via an offshore platform. According to its Acquisition Technology & Logistics Agency (ATLA), this was the first time any country had accomplished such a goal. The test would be an important step forward for the technology, with Japan aiming to utilize it both at sea and on land.

ATLA, which is part of Japan's Ministry of Defense, teamed up with the Japanese Maritime Self-Defense Force (JMSDF) for the test. Hard details about what this involved precisely, and when it took place, remain limited.

Video footage of the railgun in action during the testing released by ATLA shows it firing projectiles from various angles. 

Railgun seen firing in the footage. ATLA via Twitter/X
ATLA via Twitter/X

Existing specifications for ATLA’s medium-sized electromagnetic railgun prototype — first seen in May of this year — highlight that the weapon is able to fire 40mm steel projectiles weighing 320g (or 0.7lb). At their most basic level, as The War Zone has indicated previously, railguns rely on electromagnets rather than chemical propellants to fire projectiles at very high velocities, even into the hypersonic realm.

ATLA’s railgun can fire rounds at a velocity of around 2,230m/s (Mach 6.5), as Shepard reports, and uses five megajoules (MJ), or 5 million joules (J) of charge energy. ATLA intends for it to eventually run on 20 MJ of charge energy.

At present, we don't know for sure which vessels Japan might ultimately mount future railguns to, if they actually turn into an operational reality. However, the country has previously pointed to the possibility of mounting them on at least some JMSDF destroyers. Back in 2015, for example, when the JMSDF’s first 27DD or 27DDG ships emerged — subvariants of the Atago class guided-missile destroyers — Japan Marine United (JMU) suggested the vessels could be equipped with an electromagnetic railgun due to the improved power-generating capabilities of these ships.

An artist’s conception of a railgun installed on a 27DDG ship, seen below, shows the weapon engaging a range of air- and sea-based targets. 

An artist's conception of a railgun installation on a 27DDG ship. Japan MoD via Navy Recognition

As well as being mounted on destroyers, it's possible the weapons could also find their way onto Japan's in-development multi-purpose missile defense vessels. Japan has invested heavily in the procurement of ballistic missile defense, or BMD, warships, in recent years, for use against a growing range of air- and sea-based threats, which you can read more about in these past War Zone pieces

The speeds at which projectiles can be fired from railguns would likely make them an attractive option for targeting a wide range of aerial threats at sea, including incoming hypersonic cruise, and possibly even hypersonic ballistic, missiles. It has also been reported that ATLA intends to mount a number of railguns atop land-based trucks to similarly target hypersonic missiles.  

The mid-caliber size of this railgun concept would potentially limit these capabilities to highly localized point defense of ships and high-value land targets. Other railgun concepts, like that of the U.S. Navy, which is now defunct after much hype, are based on much larger caliber designs that, while far more capable, require more complex systems and far more power and cooling than something like what Japan is testing. Still, even at 40mm, there are still major hurdles to overcome to realize a operational naval railgun system of any kind.

The road to test-firing a working example of the weapon has been a long time coming for ATLA. In 1990 the agency's Ground Systems Research Centre (GSRC) began working on a basic, smaller 16mm railgun. Then, around 2016, efforts to develop an example designed to perform anti-air and anti-ship capabilities were initiated. Video footage of a proof-of-concept example was released by ATLA in 2018, which showcased a small-caliber developmental railgun along with related support and test equipment, which can be seen below.

ATLA railgun proof-of-concept example, 2018. ATLA video screencap
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Later in May 2022, ATLA’s GSRC concluded a $47.9 million (6.5 billion Japanese Yen) contract with Japan Steel Works for research and development of a prototype railgun, which was unveiled in May of 2023 as mentioned previously.

Despite this, Japan’s development of railguns remains more crucial than ever given the growing scale of threats it faces in the Indo-Pacific. North Korea’s growing arsenal of missiles — including hypersonic weapons — pose an immediate danger to Japan. Just last year, North Korea fired a ballistic missile over the island nation before it landed further east in the Pacific Ocean. For Japan, the missile threat from Pyongyang is clearly not an idle one, with the country publicly vowing it will destroy any North Korean missile that enters its airspace. North Korea's cruise missile capabilities are also rapidly evolving, putting Japan's ships at greater risk.

Japan's railgun demonstrator firing a discarding sabot round. (Japan MOD)

Moreover, Japan also faces challenges in the region from China, and that country’s expanding missile capabilities. In particular, Japan has claims to islets in the East China Sea, such as the Senkaku Islands, which would likely be targeted by China if a conflict between the two countries were to unfold. China's anti-ship missile arsenal is more diverse than any other country and is rapidly evolving, too.

It should be noted that Japan’s commitment to developing electromagnetic railgun technology has continued despite its abandonment by the U.S. military. The U.S.’s research into advancing two electromagnetic railgun designs, one from BAE Systems and one from General Atomics, began in 2005. This was brought to an end when funding was removed as part of the Navy’s Fiscal Year 2022 Budget, the reasons for which can be explored in this War Zone piece.

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Since then, Shigenori Mishima, vice commissioner and chief technology officer at ATLA, has indicated the possibility that U.S. contractors could join Japan’s less ambitious railgun program in the future. This could well provide the U.S. military with an indirect way back into railgun technology development.

Other countries currently working towards fielding railguns include China and Turkey. That China has been developing its own railgun was first noted back in 2018, following the appearance of a Chinese naval railgun in an advanced state of development. China claims to have developed a system that can fire a 124-kg (273-lb) projectile at a speed of 700 km (435 m) per-hour in less than 0.05 seconds. The country envisions that the technology will be a core component of its future naval assets. There is still no proof as to what this railgun prototype actually achieved, but, like that of the U.S. Navy, it also was a large caliber weapon.

China's railgun prototype seen in 2018. Chinese internet

Japan’s efforts to field an operational maritime electromagnetic railgun clearly have a long ways to go still, and significant hurdles will need to be jumped over in order to achieve something truly operational. The issues with corrosive saltwater, constant shocking, extreme heat and cold, and other factors that are unavoidable in the maritime environment will have to be overcome, as well. However, the recent test does constitute an important step towards that goal.

We’ll be keeping our eyes peeled for what comes next.

Contact the author: oliver@thewarzone.com