Japan filed a diplomatic protest with China after it said four China Coast Guard vessels entered the territorial waters of the disputed Senkaku/Diaoyu Islands in the East China Sea. According to the Japan Coast Guard, the Chinese vessels entered the territorial sea of the dispute islands at 10 a.m. on Sunday, leaving after two hours.
The incident continues a year of intensified Chinese naval and coast guard incursions into disputed waters in the East China Sea. Earlier this summer, a Chinese Navy frigate entered the territorial sea of the Senkaku Islands for the first time since 2004. Later in the summer, seven China Coast Guard vessels accompanied approximately 230 Chinese fishing trawlers in disputed waters around the islands.
Japan has also protested China’s activation of a series of gas exploration platforms on Beijing’s side of an equidistance line in the East China Sea; Tokyo alleges that the Chinese rigs violate a 2008 bilateral agreement on joint resource development in the East China Sea. Japan also said it spotted radar equipment on one gas exploration platform earlier this summer.
According to AFP, Tokyo’s diplomatic protest on Sunday marks the 32nd such protest after 31 days of separate intrusions by Chinese vessels in the East China Sea this year.
The intensification of Chinese intrusions in the East China Sea this summer roughly corresponds to a decrease in tensions in the South China Sea, where China is embroiled in entitlement and territorial disputes with five claimants, including Vietnam, the Philippines, Brunei, Malaysia, and Taiwan, and one non-claimant, Indonesia.
Tensions between China and the Philippines, in particular, have ebbed after bilateral engagement between the two sides under new Philippine President Rodrigo Duterte.
Tensions between Japan and China in the East China Sea intensified after Tokyo decided to nationalize the Senkaku Islands in 2012, to prevent their sale to Shintaro Ishihara, the nationalistic former governor of Tokyo.
In 2013, China declared an air defense identification zone over much of the East China Sea, drawing sharp protest from Japan, the United States, and other regional states.