Two related disputes between Japan and China in the East China Sea flared again in early August. Between August 5 and 9, more than 200 Chinese fishing ships entered the waters around the Senkaku Islands (called Diaoyu in China), accompanied by China Coast Guard vessels. That same weekend, the Japanese foreign ministry accused China of deploying a radar system on one of its oil platforms in the East China Sea. Japan sees those platforms as a violation of the spirit of a 2008 agreement on joint exploration of resources near the two countries’ disputed continental shelf.

The two events highlighted how the two disputes—over territory and seabed rights in the East China Sea—have escalated in tandem in recent years.

The Senkaku Flotilla

More than 200 Chinese fishing vessels and seven China Coast Guard ships gathered near the Senkaku Islands from August 5 through 9. The Chinese ships repeatedly passed into the contiguous zone and territorial waters of the islands over the course of the weekend, despite warnings from the Japan Coast Guard and protests from Tokyo.

Chinese patrols within the contiguous zone and territorial sea of the Senkakus have become a regular occurrence since 2012, but the flurry of activity in August marked a serious departure from the norm. More Chinese government ships entered the contiguous zone in August than ever before. And more China Coast Guard vessels entered the territorial sea in just five days, from August 5 to 9, than had done so in any full month in almost three years.

It is unclear whether the Chinese government vessels had worked in concert with private fishing boats or had just seized the opportunity presented by the fishing flotilla. But either way, the incident marked a challenge to the uneasy status quo around the Senkakus.

The Contest for Gas Fields

On the same weekend, the Japanese Ministry of Foreign Affairs accused China of installing a radar system on a drilling platform in the East China Sea, near the median line between Japan and China. Tokyo had previously included the platform in a June 2015 release of 16 Chinese rigs whose operation it said violated the spirit of a 2008 bilateral agreement to pursue joint development in the East China Sea.

Japan claims that the maritime boundary in the East China Sea should be a median line between the territorial boundaries of China and Japan (as defined by Tokyo). China rejects Japan’s median line and, in the absence of an agreed-upon boundary, claims a 200 nautical-mile exclusive economic zone and continental shelf (the latter was extended even further in part of the East China Sea in 2012). Under the 2008 agreement, Tokyo and Beijing agreed to jointly develop an area overlapping the median line, and to pursue opportunities for Japanese companies to cooperate in the extraction of oil and gas on the Chinese side of the line, specifically in the Shirakaba/Chunxiao gas field.

Tokyo and Beijing held talks in subsequent years to implement the 2008 agreement, but efforts fizzled out in 2010, victim to renewed tensions following the Japan Coast Guard’s arrest of a Chinese fishermen in the territorial sea around the Senkakus, which sparked a diplomatic crisis. Tensions rose higher in 2012 when Japan nationalized three of the islands and China began regular patrols in the waters around them. With the 2008 agreement dormant for the foreseeable future, China undertook new oil and gas surveys in the East China Sea, as evidenced by a mobile drilling rig in the area in 2013 (images below).

(Click on an oil rig to view satellite and aerial photos.)

From mid-2013 through 2015, China built several new drilling platforms on its side of the median line. None of these platforms fall within the agreed-upon joint development zone, but Tokyo argues that they violate the agreement’s spirit since China is unilaterally extracting oil and gas, including at the Shirakaba/Chunxiao field. On October 12, 2016, the Japanese foreign ministry protested to China over evidence of flares indicating drilling at two of the platforms, bringing the number of operational rigs to at least 12. Chinese foreign ministry spokesperson Geng Shuang dismissed the complaints, saying the activities were “completely within China’s rights and jurisdiction.”

(Click on an oil rig to view satellite and aerial photos.)

Japanese defense officials began to theorize in 2015 that China might make military modifications to the East China Sea rigs. If Tokyo’s accusations about the positioning of a new radar system commonly found on patrol ships and unnecessary for gas field development is true, it would provide  China with improved maritime domain awareness capabilities over the disputed area. The platform in question, the 12th built since 2013, sits about 37 miles from the median line claimed by Japan.

Whether China intends to use its East China Sea drilling platforms for dual civilian-military use is unclear, but developments bear watching. And one thing is clear–the disputes over the Senkakus and the seabed to their north are not as separate as they appear. Tensions over one tend to bleed over to the other, heightening anxieties and limiting the political will for compromise, as happened in the aftermath of the 2008 Sino-Japanese agreement.

(View all satellite and aerial photos below.)


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