A new development. Probably just an escalation of the boat patrols, since it is with an unarmed plane. But it continues to increase the risk of greater conflict, even if unintended--the spy plane incident of 2001 brought a lot of unintended conflict due to an accident.
http://english.kyodonews.jp/news/2012/12/199078.html
A Chinese airplane entered Japanese air space over the Senkaku Islands in the East China Sea on Thursday, the top Japanese government spokesman said.
The Air Self-Defense Force scrambled F-15 jets after the Chinese Oceanic Administration airplane was spotted near Uotsuri Island at 11:06 a.m., Chief Cabinet Secretary Osamu Fujimura told reporters.
Japan Answers Chinese Plane With Fighter Jets
By YUKA HAYASHI
http://online.wsj.com/article/SB10001424127887323981504578176681539995800.html
TOKYO—Japan scrambled fighter jets over contested islands in the East China Sea after a small Chinese propeller plane entered what Tokyo considers its airspace.
Coming just three days before general elections in Japan, Thursday's move sharply escalates territorial tensions that have already damaged economic relations between the two neighbors.
The Japanese government said that eight F-15 fighter planes from the Air Self-Defense Force were dispatched to airspace over the islands after coast-guard patrol vessels confirmed the presence of a single Chinese aircraft 15 kilometers south of the island Uotsuri Jima. That's the biggest of the contested chain, known as Senkaku in Japan and Diaoyu in China.
A defense ministry spokesman said that this is the first time ever that a Chinese aircraft has intruded into any Japanese airspace.
Prior to this, Chinese ships entering the area has become such a common occurrence (after Japanese announced nationalization of some of the islands) that international news outlets don't really report on it anymore.
Examples:
Dec. 12
http://english.kyodonews.jp/news/2012/12/199040.html
Dec. 114 Chinese ships sail into Japan's territorial waters around Senkakus
Four Chinese maritime surveillance vessels entered Japanese territorial waters Thursday morning around the disputed Senkaku Islands in the East China Sea, the Japan Coast Guard said.
Chinese ships sailed in the area near the Japan-administered chain of islets claimed by China for the third day in a row and for the 17th time after the purchase of three of the islets by the Japanese government in September.
http://english.kyodonews.jp/news/2012/12/198631.html
Chinese ships sail again in Japan's territorial waters near Senkakus
NAHA, Japan, Dec. 11, Kyodo
The Japan Coast Guard confirmed Tuesday that two Chinese maritime surveillance vessels entered Japanese territorial waters around the Senkaku Islands in the East China Sea, with the Japanese government lodging a protest with the Chinese side.
It is the 15th time Chinese government ships have entered the waters since the Japanese government purchased three of the Japanese-administered islands, which are claimed by China, from a private owner in September.
More common for sailings to be in contiguous zone (outside territorial zone). I think they stopped counting after a month.
Nov. 19
http://english.kyodonews.jp/news/2012/11/194749.html
Chinese vessels sail near Senkakus for 31st day
Chinese surveillance vessels sailed Monday in an area just outside Japanese territorial waters around the Senkaku Islands in the East China Sea for the 31st consecutive day, the Japan Coast Guard said.
Since the nationalization plan, China launched and tested its aircraft carrier, and has launched its largest surveillance ship to date:
http://edition.cnn.com/2012/11/25/world/asia/china-aircraft-carrier-landing/index.html
China announced Sunday that it had landed a fighter jet on the deck of an aircraft carrier for the first time, but it may be years before the ship is fully operational.
China's "first generation multi-purpose carrier-borne fighter jet," known as the J-15, successfully completed its first landing on the Liaoning, an aircraft carrier China built using an abandoned Soviet hull, according to China's official news agency Xinhua.
The J-15's capabilities are comparable to the Russian Su-33 jet and the U.S. F-18, Xinhua reported. The Chinese-designed jet can "carry multi-type anti-ship, air-to-air and air-to-ground missiles, as well as precision-guided bombs, the report said.
http://www.china.org.cn/china/2012-12/12/content_27384812.htm
China's largest fishery patrol ship, the Yuzheng 206, started its maiden voyage from Shanghai to patrol waters near the Diaoyu Islands on Tuesday, according to the Regional Bureau of East China Sea Fishery Management of the Ministry of Agriculture.