New Deterrent from the Depths: Japan's Submarines Evolve with Vertical Launch Systems

In recent years, the security environment in East Asia has become increasingly severe, and Japan is also promoting a fundamental strengthening of its defense capabilities. Among the initiatives attracting attention is the mounting of Vertical Launching Systems (VLS) on submarines. The Ministry of Defense has decided to begin research on underwater-launched VLS that can be installed on submarines from fiscal year 2025, planning to invest approximately 30 billion yen in research over five years until fiscal year 2029. Traditionally, Japan Maritime Self-Defense Force submarines were only equipped with weapons that attack ships on or under the surface, such as torpedoes. However, by equipping them with VLS, attacks on land-based facilities using long-range missiles become possible, significantly improving Japan's deterrence.

Submarines with VLS: A New Force Combining Secrecy and Attack Power

Submarines, navigating deep underwater, are difficult to detect by satellite or radar. Therefore, even if ground bases and runways are attacked, submarines are likely to survive and retain the ability to retaliate. Submarines equipped with VLS can be said to be the key to "retaliatory capabilities from the sea."

The nippon.com article, "令和の潜水艦 : 海中からの反撃能力保有へ―難敵は『人』" (Reiwa-era Submarines: Towards Possessing Counterattack Capabilities from the Sea - The Difficult Enemy is 'People'), introduces the mounting of long-range cruise missiles on submarines as one of Japan's defense reinforcement measures. The installation of domestically produced cruise missiles with a range exceeding 1,000 kilometers and US-made Tomahawk missiles is envisioned. The ability to launch multiple missiles simultaneously will significantly enhance the submarine's attack power.

Overcoming Technological Challenges and Moving Towards a New Submarine Era

Equipping submarines with VLS is not technically easy. The Ministry of Defense recognizes that there are several challenges to overcome, including controlling hull movement during underwater missile launches, ensuring resistance to water pressure when opening launch hatches, and vertically launching guided missiles when the hull is tilted.

However, the Ministry of Defense has indicated its intention to advance research using models and simulators, and it is also prepared to focus on research into alloy technology and gas control technology for developing hulls that can withstand high water pressure.

Furthermore, an article in "海洋安全保障情報旬報 2019年3月1日－3月10日" ("Marine Security Information Weekly Report, March 1-10, 2019") points out that while the US Navy is considering reducing its aircraft carrier forces, the importance of submarines is increasing. Because submarines are cheaper than aircraft carriers and offer greater stealth, they are expected to play an important role in future maritime security.

Trends in Other Countries and the Path Japan Should Take

Submarines equipped with VLS are already possessed by the United States, China, Russia, South Korea, and North Korea. Japan also needs to modernize its submarines to counter threats from neighboring countries.

The article "Malaysia's right to stake claim to Spratlys" addresses the issue of territorial rights in the South China Sea. China is strengthening its maritime advance, increasing tension with neighboring countries. For Japan to protect its maritime rights and interests, strengthening its maritime defense capabilities, including submarines, is essential.

The article "Second track on Indo-Pacific and the Quad" discusses the importance of the Quadrilateral Security Dialogue (Quad) among Japan, the United States, Australia, and India. The Quad is a framework for security cooperation in the Indo-Pacific region, and is expected to deter China's maritime advance. Japan should contribute to regional peace and stability through multilateral cooperation such as the Quad.

The Potential of Submarines: From Deterrence to Diverse Missions

In addition to their traditional anti-ship and anti-submarine missions, submarines hold the potential to serve as platforms for various missions, including intelligence gathering, mine laying, and special forces transport.

The article "Pakistan’s Navy Spotted, Warned Indian Submarine in Arabian Sea" claims that the Pakistani Navy detected an Indian Navy submarine. This demonstrates that submarines are effective for reconnaissance and surveillance activities due to their stealth capabilities.

The article "Netanyahu: Israeli Navy Could “Block” Iranian Oil Shipping" suggests the possibility of the Israeli Navy blocking Iranian oil shipments. This is an example demonstrating that submarines can be used to interdict sea lanes.

Conclusion: The Role of Submarines in Japan's Security

Submarines play an important role in Japan's security. The improvement of offensive capabilities through VLS mounting will significantly strengthen Japan's deterrence and counter threats from neighboring countries. Going forward, Japan needs to overcome technological challenges and maximize the capabilities of its submarines to cope with the new security environment. Submarines will be an indispensable presence in protecting Japan's peace and prosperity.