Japan’s Naval Modernization and Gradual Transition to Assertive Posture

Japanese Maritime Self-Defense Force (JMSDF), as the name implies, is traditionally designed for defending Japan’s main islands and regional territories. Through-out Cold War, Japan has focused towards North and West primarily due to its territorial disputes with Soviet Union on Kuril Islands. JMSDF, despite active collaboration with United States Navy (USN) in Pacific Theatre, sustained defensive posture in accordance with national interests. But in recent decades, the rapid rise of China as a major power has transformed the regional power dynamics. Beside abrasive historical relations between Beijing and Tokyo, the interactions between both nations are also characterized by territorial disputes in maritime domain. Territorial dispute between China and Japan exists in the East China Sea involving a cluster of five small, uninhabited islands known as the Senkaku in Japan and the Diaoyu in China. The sovereignty over these islands has been a source of contention among China, Japan, and even Taiwan for decades. In recent years, naval and air forces from both China and Japan have frequently encountered each other as both nations vie to assert control and demonstrate their respective claims over these disputed islands.

JMSDF surface fleet is one of the largest in the world and primarily known for its large destroyer fleet. JMSDF currently operates four landing helicopter docks (LHDs), three major amphibious warships (LSTs), eight aegis-equipped heavy destroyers, 28 multi-mission destroyers, and numerous patrol and support vessels. JMSDF underwater arm, equipped with fleet of 22 diesel electric submarines (SSKs), is also predominately defensive in nature. Being diesel electric, these submarines have shorter range and limited endurance thus suitable to ascertain sea-denial operations. JMSDF’s Fleet Air Force currently operates large fleet of fixed wing and rotary wing aircrafts. With 68 units operational, the primary Maritime Patrol Aircraft (MPA) is turbo-prop P-3C Orion. The ship-borne ASW duties are performed by SH-60J/K ASW helicopters which are also operated from land bases. Since recently, the surface, aerial, and underwater fleets of JMSDF lacked any long range offensive munitions and were configured predominately for defensive duties.

Japanese late prime minister, Abe Shinzo, has played key role in shifting the Japan’s posture from a purely pacifist state to a state with dynamic retaliatory posture. With China’s naval expansion in sight, Japan’s naval modernization programs are now directed towards South and focused on attaining necessary counterattack capability in tandem with strengthening the defensive potential. This is also evident in rapidly increasing annual defense budget from past several years. Japan’s Cabinet has approved $56 billion defense budget for fiscal year 2024 – the largest amount ever since WW-II.

Japan’s progressive build-up of naval capabilities emerges as an indication of strategic alignment for countering China with the United States, India, and Australia in the form of Quad. Through joint exercises, like Malabar, strategic dialogues, and the forging of new alliances, Japan seeks to synergize its naval capabilities with Quad partners, fostering interoperability and a coordinated response to diverse maritime challenges.

Japan’s Ministry of Defense White Paper (2023) has outlined two key priorities for modernization of its armed forces. First, maximizing efficiency of existing equipment and acquiring munitions in sufficient numbers; second, augment key domains of future defense potential particularly stand-off defense capabilities that can be employed for counterstrike role. Japan seeks to reinforce deterrence by developing multilayered defensive as well as multi-platform stand-off counterstrike potential.

The pivot of Japan’s force modernization is based on acquisition of F-35 Lightening-II stealth aircrafts. With total order of 157 airframes, Japan is currently the largest customer of F-35 in world. Interestingly, out of 157 airframes, 42 are F-35B – a short take off and vertical land version (STOVL), which Japan will deploy on it two Izumo class landing helicopter docks (LHDs). Both Izumo class LHDs are being retrofitted to embark F-35B Lightening-II stealth aircrafts. Once fully modified, both vessels will essentially turn into light aircraft carriers armed with the most advance carrier borne fighter aircraft in the world. In comparison with United States’ carrier-borne naval aviation, JMSDF capability will be of modest scale. But the incorporation of carrier-borne stealth fighter aircrafts will add new dimension in offensive and defensive capability of JMSDF.

After scarping plans for installing Aegis-Ashore Ballistic Missile Systems, Japan is now in process of building two aegis-equipped heavy missile-defense destroyers now referred as Aegis System Equipped Vessels (ASEVs). Displacing more than 12,000 tons, these heavy warships will be equipped with offensive and defensive missiles of varying ranges and will develop multi-layer missile defense envelop over Japan. The deployment of both ASEVs could free Japan’s other aegis-equipped destroyers from ballistic missile defense patrols in the Sea of Japan. This will eventually allow Japan to configure and employ its remaining destroyer feet for other broader spectrum of operations, particularly around the Ryuku Islands. In comparison with land based fixed aegis-ashore site, these missile defense warships will be mobile and could be deployed to different places according to threat requirements. Both ASEVs are expected to join JMSDF by end of 2028.

In parallel, JMSDF is in process of replacing older generation destroyers with Mogami class frigates. These frigates are designed to be stealthier, and highly automated with primary role of conducting anti-submarine warfare (ASW) duties. Initially twelve Mogami class frigates will be built with eventual planned total of 22 frigates. Currently six ships of this class are operational and have enhanced ASW capabilities of JMSDF surface fleet by many folds.

In underwater domain, JMSDF will be gradually acquiring Taigei class submarines to replace older boats. Recently developed Taigei class submarines incorporate electric propulsion system (lithium-ion batteries) which allows longer endurance and significantly reduces acoustic signature. Due to these features, these subs are regarded as next generation class in category of conventional powered submarines. The stealth features and ability to fire UGM-84L Harpoon block-II SLCM from torpedo tubes enable these subs to strike enemy surface assets. In total, JMSDF will be inducting six such submarines. In sum, the near future surface fleet of JMSDF will comprise of two light aircraft carriers, two landing helicopter dock, two ASEVs, eight aegis-equipped heavy destroyers, six multi-mission destroyers, 22 stealth ASW frigates with numerous patrol and support vessels.

Japan’s naval modernization reflects a significant shift in its defence strategy, marking a gradual transition to a more assertive posture. This evolution is driven by the changing dynamics of East Asia, particularly the growing influence of China. The comparison of contemporary and near future vessels of JMSDF suggests that the numerical strength of JMSDF will not see considerable increment in size. However, the force will be highly modernized with significantly enhanced offensive capabilities. This fleet will be able to project power at multiple tiers as well as undertake traditional defensive duties at the same time. By enhancing its naval capabilities and adopting a more assertive posture, Japan is not only safeguarding its own sovereignty but also playing a crucial role in maintaining the balance of power in the Indo-Pacific.