Japan has successfully tested a medium-caliber maritime electromagnetic railgun via an offshore platform, signaling the potential for a high-tech transformation of Tokyo’s defensive posture, according to a Warzone report.
Japan’s Acquisition Technology & Logistics Agency (ATLA), part of the country’s Ministry of Defense (MOD), teamed up with the Japanese Maritime Self-Defense Force (JMSDF) for the test.
Video footage of the railgun in action during the testing released by ATLA shows it firing projectiles from various angles. A railgun uses electromagnetic energy to propel projectiles at extremely high velocities potentially reaching hypersonic speeds, in contrast to chemical propellants used by traditional guns. Japan would reportedly deploy the weapon on land and at sea.
The Warzone report says that ATLA’s medium-sized electromagnetic railgun prototype can fire 40 mm steel projectiles weighing 320 grams each, judging by the weapon’s specifications. It says ATLA intends to eventually run its gun on 20 megajoules (MJ) of charge energy.
It is unknown which vessels Japan might ultimately mount future railguns on when they become operational for deployment.
However, Japan has previously pointed to the possibility of mounting them on some of its JMSDF destroyers, according to the Warzone report. They could also be mounted onto Japan’s in-development multipurpose missile defense vessels, the report says.
Japan’s successful development of railguns is as crucial as ever given the growing scale of threats it faces in the Indo-Pacific, including China and North Korea’s growing missile and hypersonic weapon arsenals.
The railgun race is on in the region. Reports indicate China may have been testing the technology since 2018. Its ship-mounted railgun has apparently been mounted on a Type-072 landing ship modified to house the weapon’s bulky electronics.
Japan has other high-tech weapons projects in the works. This month, Naval News reported that Japan’s MOD has announced research and development plans for future naval systems, particularly those related to the naval domain.
Naval News notes that these include Combat Support Multipurpose Unmanned Surface Vessels (USV), unmanned amphibious assault vehicles (AAV), anti-torpedo torpedoes (ATT) and combat management systems.
Naval News notes that Combat Support Multipurpose USVs are large, unmanned surface vessels that can be operated autonomously or remotely from a land-based control facility. It says they aim to replace payloads such as sensors, anti-ship missiles and torpedoes depending on the mission and can evade enemy threats by submerging itself.
The report says unmanned amphibious vehicles are designed to secure beachheads ahead of manned AAVs. It notes that they must overcome reefs using powerful propulsion and employ electric power-assist technology to compact the chassis and free up interior space.
Naval News also says that the JMSDF is angling to add the ability to neutralize high-performance torpedoes launched by enemy submarines. The program seeks to improve the capability of Type 12 torpedoes and the sonar of destroyers equipped with them to detect enemy torpedoes at an early stage.
To counter hypersonic threats, Japan is jointly developing the Glide Phase Interceptor (GPI) with the US and working on a domestically produced system for future destroyers. As part of the program, a new multi-band radar will be developed to detect high-speed, highly maneuverable, small targets alongside a new Combat Management System (CMS) for destroyers.
Naval News says that Japan is also developing the so-called New Ship-to-Air Missile (N-SAM), which will be designed to counter Hypersonic Glide Vehicles (HGVs). The N-SAM will be based on the New Ship-to-Air Missile (N-SAM) recently procured by the JMSDF as part of the 2024 fiscal year defense budget.
The N-SAM will have an improved capability to detect, track and engage HGVs that fly at high altitudes, speeds and irregular trajectories via improved fire control systems (FCS) installed abroad destroyers. These various types of equipment to counter HGVs will be installed on the new destroyers scheduled to be built in 2031 and retrofitted on existing ships, Naval News says.
Japan’s alliance with the US may have been instrumental in the success of its railgun project. In an April 2023 article for National Defense Magazine, Stew Magnuson says that Japan has looked to partner with the US on a railgun program aimed at defeating hypersonic weapons.
Magnuson mentions that Japan has sought to partner with the US in railgun technology, despite the US Navy abandoning the technology in 2021 after 15 years of research and US$500 million spent to develop a railgun for its destroyers.
Magnuson notes that Japan Steel Works is the primary contractor for Tokyo’s program. He mentions that American defense company General Atomics Electromagnetic Systems has worked with Japan’s ATLA and Japan Steel Works to discuss Japan’s railgun program.
Magnuson also notes the challenges in using ship-based railguns to counter hypersonic weapons, including their substantial power requirements and risk of overheating. He suggests that a land-based version could help resolve those issues.
More broadly, US-Japan railgun collaboration may offer a way to integrate Japan into a technocentric US-led Pacific security architecture. Due to language, culture, political and historical differences, Japan’s inclusion in the high-tech AUKUS alliance comprised of the US, UK and Australia would be challenging.
Moreover, Japan’s reservations about the military use of nuclear technology would prevent it from participating in AUKUS’s nuclear submarine program, a key component of the alliance.
However, the introduction of Combat Support Multipurpose USVs and unmanned AAVs alongside long-range counterstrike capabilities may signify a change in Japan’s traditional defensive military posture to a more offensive expeditionary-oriented one.
Takashi Morimoto writes in a February 2023 US Naval Institute article that unmanned ship systems embedded in the JMSDF’s fleet would sustain operational capabilities in the Sea of Japan and help fill the gap created by redeploying part of the fleet to Okinawa.
Morimoto also says that the Japan Self-Defense Forces (JSDF) must become more jointly oriented, increase their expeditionary capability and overcome distance disadvantages.
Meanwhile, Jr Ng mentions in a January 2023 article for Asian Military Review that unmanned AAVs can support logistics operations such as transporting personnel and supplies while minimizing casualties as advance elements of an amphibious landing operation to retake remote islands.
Still, Japan’s reorientation toward expeditionary warfare capabilities faces significant strategic, operational and tactical challenges.
Benjamin Schreer writes in an October 2020 article for War on the Rocks that while a significant part of Japan’s defense modernization efforts are geared toward the development of amphibious warfare capabilities, they neglect China’s increased ability to target big amphibious ships and support elements.
Schreer says Japan’s amphibious capability remains nested in a risky, potentially outdated defense strategy for deterring China’s growing and increasingly sophisticated military power.
Schreer recommends that Japan should change its amphibious warfare approach centered around large, vulnerable landing ships geared to retake contested islands to an “active denial” defense strategy.
That strategy, he writes, should seek to build up a more resilient Japanese capability to frustrate Chinese power projection in a prolonged campaign rather than seeking its early, swift defeat in the inner anti-access/area denial (A2/AD) ring.
He suggests that Japan’s amphibious forces should conceive themselves as elite commando units or “marine raiders” charged with alternative amphibious missions in a broadened concept of “island defense.”