
The Japanese Maritime Self-Defense Force (JMSDF) is a highly capable navy, although it is the smallest of Japan’s military branches. It is technologically more advanced, more experienced, and more highly trained than its main competitor – the People’s Liberation Army Navy (PLAN). Yet, in the long-run, the JMSDF and the Japanese Coast Guard (JCG) – Tokyo’s principle enforcer of maritime law – are at a relative disadvantage if one looks at the bourgeoning naval rearmament program of China, which is gradually shifting the regional maritime balance in Beijing’s favor.

“From a military perspective, Tokyo is becoming the weaker party in the Sino-Japanese rivalry,” argues Naval War College professor Toshi Yoshihara, in a 2014 report by the Center for a New American Security (CNAS). “Japan (…) finds itself squeezed between China’s latent military prowess that backs up Chinese coercion over the Senkaku/Diaoyu Islands dispute and China’s ability to disrupt access to the global commons should conventional deterrence fail,” he further notes.

According to the Institute of International Strategic Studies, China’s share of regional military expenditure rose from 28 percent in 2010 to 38 percent in 2014 totaling $129.4 billion. In contrast, in Japan, despite fears of resurgent militarism under Shinzo Abe, regional share of expenditure fell from 20 percent in 2010 to less than 14 percent in 2014, leaving Tokyo’s defense budget at $47.7 billion.

Given Tokyo’s apparent relative decline in military strengths what is the JMSDF’s best strategy for confronting China in the years ahead?

According to Toshi Yoshihara, it is an anti-access operational concept with Japanese characteristics. In short, Japan should give China a dose of its own medicine and emulate the PLAN’s alleged anti-access/area denial (A2/AD) strategy (although there is little actual evidence that the Chinese Navy is placing a high priority on such a strategy. See: “The One Article to Read on Chinese Naval Strategy in 2015”). An A2/AD operational concept with Japanese characteristics would take into account Japan’s role as a gatekeeper to the open waters of the Pacific and would center around exploiting Japan’s maritime geographical advantage over China by skillfully deploying the JMSDF along the Ryukyu Islands chain, bottling up the PLAN in the East China Sea until the U.S. Navy and other allied navies can deploy in full-strength.

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The short-term operational goal would be to create a military stalemate, until superior allied forces could be brought to bear. “While the Ryukyus fall well inside the PLA’s antiaccess zone, the archipelago’s strategic location offers Japan a chance to turn the tables on China. By deploying anti-access and area-denial units along the islands, Japanese defenders could slam shut an important outlet for Chinese surface, submarine and air forces into the Pacific high seas,” Toshi Yoshihara notes.

Bernard D. Cole, in his book, Asian Maritime Strategies – Navigating Troubled Waters, argues that “although not formally promulgated,” Japan is “essentially” already for all intents and purposes pursuing an anti-access/area denial (A2/AD) strategy – albeit not a comprehensive one, given the current much broader mission set of the JMSDF. The linchpin of Tokyo’s A2/AD strategy is undersea warfare, which promises to be an effective A2/AD tool given the PLAN’s poor anti-submarine warfare capabilities as outlined in a recent RAND report on Chinese military weaknesses.

Submarines are the JMSDF’s capital ships. In 2010, the Japanese Navy announced that it would increase its submarine fleet from 16 to 22 ships. The backbone of the new fleet will be ten Soryu-class diesel-electric attack submarines, five of which are already in service, with the rest commissioned by 2019. The Soryus are among the biggest and most technologically advanced diesel submarines in the world. The JMSDF also continues to operate 11 Oyashio-class diesel-electric class submarines.


“To patrol the waters along southwestern Japan, it is estimated that at least eight submarines are necessary (six for the Okinawa island chain and two for the Bashi Channel). Typically, a boat requires two backups for training and maintenance. Thus a submarine fleet of 24 is ideal, but a fleet of 22 provides more operational flexibility than the current fleet of 16,” summarizes Tetsuo Kotani, a senior research fellow at the Japan Institute of International Affairs, in a 2014 paper on the U.S.-Japan allied maritime strategy, the rationale behind Japan’s submarine buildup. Kotani also supports an A2/AD strategy with Japanese characteristics: “To deter Chinese aggression, Japan and the United States should maintain sea-denial capabilities inside the first island chain and sea control beyond the first island chain.”

There are indications that Japan is tacitly pursuing an A2/AD strategy. Two new Izumo-class helicopter destroyers (22DDH) with 20,000 tons full-load displacement, and capable of carrying 15 helicopters, will enhance the JMSDF anti-submarine warfare and border-area surveillance capabilities, and could also be used to quickly ferry troops (e.g., anti-ship and anti-air missile units) to the Ryukyu Islands. In addition, Tokyo plans to add 20 Kawasaki P-1 maritime patrol aircraft, capable of conducting anti-submarine warfare, to its naval arsenal. By the end of fiscal year 2020, the JMSDF also plans to double the number of Aegis-equipped destroyers from four to eight, with the possibility of adding two more past 2020. The destroyers will boost the JMSDF’s anti-air-warfare capability – a crucial component of any A2/AD strategy.

Additionally, the JMSDF plans to add at least two more ships to its already existing fleet of 27 mine-warfare vessels. Japan possesses a very large inventory of sophisticated anti-ship mines, some of which are specifically designed to target vessels passing through narrow seas. Japan’s 2012 Defense White Paper specifically talks about “mine deployment warfare”. “[T]he Japanese mine threat would be very challenging to China in times of hostilities. Chinese minesweeping units and associated escorts would have to cross several hundred kilometers of hotly contested waters and airspace to reach the Ryukyus,” elaborates Toshi Yoshihara. Fast-attack boats (e.g., the Hayabusa-class guided-missile patrol boat), hiding behind occupied islands and stealthily launching anti-ship missiles, could make matters even worse for the PLAN, should Chinese naval forces attempt a breakthrough.

The big question is whether the Chinese PLAN constitutes such a threat to Japan that it would justify the JMSDF pulling all resources into implementing a comprehensive “Anti-PLAN A2/AD Strategy.” As of now, the answer is clearly no. While an A2/AD cost-imposing strategy may deter the PLAN from trying to break out of the East China Sea bottleneck in times of war, it will do very little to help alleviate other maritime issues such as settling “gray-zone disputes” (e.g., the ongoing conflict over the Senkaku/Diaoyu Islands), stemming the North Korean threat, or fulfilling the JMSDFs mission to defend regional sea lines of communication (the Tokyo, Guam, Taiwan triangle), which, in fact, is Tokyo’s responsibility under the mutual defense treaty with the United States – the cornerstone of the country’s security.

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Defending regional sea lines of communications necessitates a broader set of skills than is needed for an A2/AD strategy and “requires proficiency across the spectrum of both coast-guard and naval missions, from surveillance to defense against ballistic missiles,” according to Bernard D. Cole. Unless, Japan’s defense budget will rise substantially, compromises will have to be made. Yet, with seaborne shipping carrying 99.7 percent of Japan’s overall trade, Japan cannot compromise over a well-balanced and adaptable maritime strategy — it is an absolute necessity for the country. It has to be a fox rather than a hedgehog, to use Isaiah Berlin’s analogy when analyzing Tolstoi, for “the fox knows many things, but the hedgehog knows one big thing.”

Consequently, while Japan is currently tacitly pursuing a partial A2/AD strategy, it needs to balance the Chinese naval threat with other emerging threats and the multiple maritime responsibilities of a regional great power. It follows that although a comprehensive “Anti-PLAN A2/AD Strategy” may be the fastest way to victory in a military confrontation with China, it is unlikely that we will see a major change in Japan’s maritime strategy in the near-term future.