Chinese research vessels have operated several times this year inside Japan's exclusive economic zone near the Diaoyutai Islands, and Japanese authorities assess that the activity may be preparation for the use of force against Taiwan — bad news for both Taiwan and Japan.

• The research vessel "Xiang Yang Hong 22" carried out repeated surveys in Japanese waters west of the Diaoyutai Islands on five occasions between March and July, and also lowered a tubular device into the sea.
• Thirteen such unauthorised surveys have already taken place this year, compared with only six in all of last year — more than double the number.
• Japan regards this as a violation of the United Nations Convention on the Law of the Sea, and has lodged protests through diplomatic channels while stepping up surveillance.
• Data on seabed topography, water temperature and ocean currents can be put to military use, and is critical for selecting submarine routes and for sonar operations.
• The same Chinese research vessel also appeared in waters north of Taiwan last year, where it was driven off by the Coast Guard Administration.

Outlook: Chinese maritime surveys around the Nansei Islands and Taiwan will only become more frequent in the near term, and the pressure on Japanese and Taiwanese maritime surveillance will rise accordingly.