Japan has protested the “extremely dangerous” behaviour of a Chinese helicopter which buzzed a Japanese destroyer in the East China Sea. From the BBC:

The Japanese ship was on patrol on Monday near a disputed gas field that both countries want to exploit.

Relations between the two nations have been strained since a row last year over the arrest of a Chinese trawler captain near islands both claim.

Japan’s Defence Minister Toshimi Kitazawa called the aerial manoeuvre by the Chinese helicopter “extremely dangerous”.

Officials say it flew within 70m (230ft) of the Japanese destroyer, Samidare, at an altitude of less than 40m.

The Financial Times challenges the BBC’s account of the incident’s location, however:

A Japanese defence ministry official declined to give details of where the latest incident occurred, but denied media reports it was near the controversial Chunxiao gas field, where Tokyo says Chinese drilling operations could be drawing gas from across the “median line” that it claims as the border of its EEZ.

Japan did issue a separate complaint this week regarding alleged Chinese drilling in the Chunxiao field, however.

As the articles note, last week saw Japan scramble fighters to head off Chinese aircraft approaching the Senkaku/Diaoyu Islands, and the Philippines complain about the menacing of one of its survey vessels by Chinese patrol boats in the South China Sea. In addition, Vietnam protested that a pair of Chinese missile destroyers had conducted exercises in its waters.

New fears for Japan’s security were sparked on Sunday by the resignation of foreign minister Maehara Seiji. During his six months in office, Maehara had sought to repair the somewhat dented alliance with the US, a strategy designed to complement the reorientation of the country’s defences away from the former Soviet Union and toward China. His departure threatens to undermine this renewed relationship with Washington, according to The Japan Times:

Takashi Kawakami, a professor of securities issues at Takushoku University, said the resignation of Maehara, known for his pro-Washington stance, will damage ties with the United States and expose Japan more to hardline China and Russia.

“If Japan can’t deepen ties with the U.S., that means Japan’s deterrence will go down,” Kawakami said, predicting China will get more aggressive around the Senkaku Islands and Russia will strengthen its grip over the four islands it holds off Hokkaido ….

Kawakami, an expert on Japan-U.S. relations, said the shock of the resignation has spread throughout Washington, where officials considered Maehara the most likely candidate to succeed Kan. But with Maehara out of the picture, the future of relations has, once again, become unclear.

Prime Minister Kan Naoto has since named Matsumoto Takeaki, a Senior Vice Foreign Minister under Maehara, as the new Foreign Secretary, suggesting a degree of continuity which may help lay these fears to rest.

China Daily reported this week that the International Institute of Strategic Studies has formally classified Japan as an “aircraft-carrier power”, leaving China encircled by four such countries: Russia, Japan, India and Thailand. Japan’s carrier has actually been afloat since 2007, but was previously categorised as a “helicopter destroyer”, a term thought to dance more nimbly than “aircraft carrier” around the constitutional prohibition on offensive weaponry. Nevertheless, the Hyuga-class vessel could potentially serve as a launch platform for planes as well as helicopters:

“The Hyuga is not yet as powerful as the Japanese Maritime Self-Defense Force (JMSDF) would like it to be, mainly because there are no F-35s (fighter jets) as yet,” Li said.

“Once Japan acquires F-35s or another suitable short take-off aircraft for the Hyuga class, it will have a greatly increased expeditionary capability, and can operate in conjunction with the US more and more in regional security operations.”

Li said the JMSDF is “very powerful” in terms of capabilities. “Its assets are arguably the second best after the US. The ships are modern, powerful, and with a wide range of services. However they suffer from the same problems as the Chinese navy in that it lacks expeditionary capabilities and also the crew lack real battle experience.”