The incident is the first in the East China Sea since Abe and Xi met at the 2016 G20 meeting in Hangzhou, China.


On Sunday, the Japanese government said that four China Coast Guard ships entered territorial waters around the disputed Senkaku/Diaoyu Islands in the East China Sea. The vessels entered the 12 nautical mile territorial waters around the islands at approximately 10:30 a.m. on Sunday, leaving after 90 minutes. Japan administers the Senkaku/Diaoyu Islands, which are claimed by China.

Sunday’s incident marks a continuation of ongoing tensions between Japan and China in the East China Sea that intensified earlier this year after a period of relative calm. Sunday’s incident is additionally the first in the East China Sea since Chinese President Xi Jinping and Japanese Prime Minister Shinzo Abe met briefly on the sidelines of the Hangzhou G20 meeting in China.

At that meeting, which was the first between Abe and Xi in 17 months, the two leaders agreed to “accelerate talks for establishing a communications mechanism between the two countries’ naval and air forces.” China and Japan have been pursuing a crisis management mechanism for the East China Sea for more than a year. Both China and Japan are additionally party to the Code for Unplanned Encounters at Sea (CUES), which was finalized at the 2014 Western Pacific Naval Symposium.

Earlier this summer, for the first time ever, a Chinese Navy frigate entered the contiguous zone around the disputed Senkaku/Diaoyu Islands. The contiguous zone is a 12 nautical mile area adjacent to the territorial sea where coastal states can administer customs, immigration, and other laws.

More recently, in August, several armed China Coast Guard vessels, accompanied by more than two hundred fishing boats, were spotted in the territorial seas of the Senkaku/Diaoyu Islands. Moreover, Japanese authorities reported in August that they had spotted radar equipment on a Chinese gas platform in the East China Sea, albeit not near the Senkaku/Diaoyu Islands and on the Chinese side of a geographical equidistance line between Tokyo and Beijing’s claimed areas.