As the world pays attention to the recent Chinese militarization of the South China Sea islets, China is establishing a “new normal” with more frequent military and paramilitary presence in the East China Sea. China is taking necessary steps to make the South China Sea a Chinese lake with surveillance and air defense assets deployed. But it is less likely that the East China Sea will become a Chinese lake because the military balance still favors Japan.
China’s assertiveness in the East China Sea reflects Beijing’s challenge to the regional order based on the 1951 San Francisco Peace Treaty. Under this Treaty, the Senkaku Islands as part of Okinawa were placed under U.S. trusteeship and returned to Japan under the 1972 Okinawa Reversion Treaty. China, which was not a party to the peace treaty, started to claim the Senkaku Islands in 1971 based on the 1895 Treaty of Shimonoseki and the 1943 Cairo Declaration.
Beijing launched physical challenges to Japanese administration of the Senkaku Islands in 2008, when two Chinese government ships intruded into Japanese territorial waters around the Islands. The frequency of intrusions increased dramatically after September 2012 and gradually declined in the latter half of 2013. But Chinese ships, including armed coast guard ships converted from warships, maintain presence around the Senkaku Islands.
China’s attempts to establish a “new normal” also reflect growing anti-access/area-denial (A2/AD) strategy in the East China Sea. Since 2008, China’s naval surface and submarine fleet activities have grown increasingly frequent in the East China Sea and beyond in an effort to improve access to the open ocean and develop its A2/AD capabilities. The most frequently used route is the Miyako Channel between Mainland Okinawa and Miyako Island, the widest gap along the first island chain.
Chinese military aircraft activities also increased after 2010, and China announced the “East China Sea Air Defense Identification Zone” in November 2013. The flight patterns of Chinese aircraft indicate that the coastal radar system covers only the western half of the East China Sea, and the airspace beyond the geographical median line remains a blind spot. Under such a circumstance, there is a growing concern that China might militarize some of the 16 offshore gas platforms along the median line for surveillance and better air domain awareness.
Facing China’s assertive behavior to establish a “new normal” in the East China Sea, Japan revised the National Defense Program Guidelines in 2013, which called for a dynamic joint defense force. The dynamic joint defense force concept envisions air and maritime superiority with active and regular surveillance, plus rapid deployment of amphibious troops, armored vehicles, air-defense units, and surface-to-ship missile launchers in defense of the Nansei (Southwestern) Islands. In essence, it is a Japanese version of an A2/AD strategy in the East China Sea.
To deal with Chinese challenges in the East China Sea more effectively, Japan also strengthened its alliance with the United States. President Barack Obama confirmed the U.S. treaty commitment to the Senkaku Islands during his visit to Tokyo in April 2014. Following this, Tokyo and Washington revised the bilateral defense cooperation guidelines to upgrade bilateral operational cooperation. Under the new Guidelines, the Japan Self-Defense Force takes the primary responsibility for the defense of Nansei Islands, while the U.S. military plays a supporting role with long-range strike capabilities.
Japan is now better able to respond to Chinese assertiveness in the East China Sea. But probably because the overall military balance in the East China Sea favors Japan and the United States, China has adopted an approach characterized by gray-zone coercion, short of war. Seeking to remain below the threshold of military power that would lead to a joint Japan-U.S. military response, China has regularized the presence of its coast guard ships in the vicinity of the Senkaku Islands. While China has been deterred from the use of overt military force, its gray-zone coercion has not been deterred by the strengthened U.S.-Japan alliance.
The East China Sea is not likely to become a Chinese lake. To defend its sovereignty and rules-based regional order, however, Japan needs to respond more effectively to Chinese gray-zone coercion.