Chinese demonstrators raise their national flag while a police helicopter is flying over during a protest against Japan in Shenzhen, China Sept. 16, 2012. Protesters held demonstrations against Japan, after protests over disputed islands spread across numerous cities and at times turned violent. Apple Daily/AP
In this Sept. 2, 2012 file photo, the survey ship Koyo Maru (l.), chartered by Tokyo city officials, sails around Minamikojima (foreground) Kitakojima (center r.) and Uotsuri (background), the tiny islands in the East China Sea, called Senkaku in Japanese and Diaoyu in Chinese. Kyodo News/AP
Activists holding Chinese and Taiwanese flags are arrested by Japanese police officers after landing on Uotsuri Island, one of the islands of Senkaku in Japanese and Diaoyu in Chinese, in the East China Sea on Aug. 15, 2012. Yomiuri Shimbun/AP
Taiwan Coast Guard personnel inspect the fishing boat on which Taiwanese activists took to the disputed East China Sea islets, called Senkaku in Japan, Diaoyu in China, and Tiaoyutai in Taiwan after it was ashore at the port of San-ao in New Taipei City, northern Taiwan, January 24, 2013. Pichi Chuang/Reuters
A Chinese flag and a satellite dish are prominently displayed in a structure built by China in one of the islands in the Spratlys, in the South China Sea, in this May 1995 photo. First came the diplomatic offensive, then the flexing of military muscle. Now, China is opening a third front to assert its claims in the South China Sea - moving ahead with its first major tender of oil and gas blocks in disputed parts of its waters. Reuters
A small boat is lowered from the survey ship Koyo Maru, chartered by Tokyo city officials, near Uotsuri (r.) one of the tiny islands in the East China Sea, called Senkaku in Japanese and Diaoyu in Chinese, Sept. 2, 2012. Tokyo city officials, planning to buy the islands at the center of a longtime territorial dispute with China, surveyed the area on a visit meant to send a message of ownership. Kyodo News/AP
Tokyo city officials and experts on a small boat enter a cave on Uotsuri, one of the tiny islands in the East China Sea, called Senkaku in Japanese and Diaoyu in Chinese, Sept. 2, 2012. Kyodo News/AP
A boat (c.) is surrounded by Japan Coast Guard patrol boats after some activists descended from the boat and landed on Uotsuri Island, one of the islands of Senkaku in Japanese and Diaoyu in Chinese, in the East China Sea, Aug. 15, 2012. Yomiuri Shimbun/AP
Filipino naval personnel look at giant clam shells on board a Chinese fishing vessel at the disputed Scarborough Shoal in the South China Sea, near the Philippines, April 10, 2012. The Philippine government said it agreed with China to diplomatically resolve a tense standoff involving a Philippine warship and two Chinese surveillance vessels in the disputed South China Sea when its navy tried to detain Chinese boats fishing in its waters, but was stopped by two Chinese surveillance craft. Philippine Navy/AP
Protesters chant anti-China slogans as they march towards the Chinese consulate in Manila's Makati financial district May 11, 2012. About 200 Filipino activists, carrying placards and banners and waving small Philippine flags, held a noisy but peaceful protest outside a Chinese consular office in Manila over Scarborough Shoal islands in the South China Sea claimed by both nations. Erik De Castro/Reuters
Chinese Defense Minister Liang Guanglie inspects a Guard of Honor in New Delhi, India, Sept. 4, 2012. The defense ministers of India and China agreed to resume military exercises, signaling a thaw in military ties despite an ongoing dispute over Beijing's territorial claims in the South China Sea. Manish Swarup/AP
A border guard stands on a small boat in front of a US naval ship, docked at Tien Sa port, in Vietnam's central Danang city July 15, 2011. In June 2011, Vietnam's Foreign Ministry said the US would engage in joint naval activities with the Vietnamese, describing them as regular annual events. Tensions are high in the region over concern that China is becoming more assertive in its claim to disputed areas of the South China Sea believed to be rich in oil and gas. Kham/Reuters
China sent a fleet of patrol ships today to the sea area it disputes with Japan, following a controversial visit by Japanese officials to a war shrine. The latest moves are seen as a setback for a diplomatic resolution.
Spats between Asia’s two most powerful nations, China and Japan, have grown uncomfortably routine since Tokyo nationalized a group of disputed islands in September. On Tuesday tensions reached a new and potentially worrisome high.