China’s moves in disputed waters spark concerns in Japan about ‘incremental control’

Japan has lodged a protest with Beijing over the suspected construction of a new offshore platform in disputed waters of the East China Sea – a development that analysts say could signal China’s latest attempt to extend administrative control through incremental moves.

The protest came after satellite imagery showed two large Chinese ships positioned roughly 345km northwest of Kume Island in Okinawa prefecture – an area where the countries’ exclusive economic zones (EEZs) overlap and remain subject to a long-running maritime dispute.

The images, released by the European Space Agency and analysed alongside data from the international Automatic Identification System, identified the vessels as the 297-metre crane ship Zhenhua 30 and the 160-metre heavy-lift ship Debo 3.

Both ships have remained in the same location since May 11, according to Japanese newspaper Sankei Shimbun, supported by a flotilla of supply ships and tugboats. Japan’s coastguard has reported that the activity appears linked to the construction of an “offshore platform”.

Tokyo lodged a formal complaint through China’s embassy in Japan, citing the platform’s location within overlapping EEZ claims and warning against unilateral actions that could alter the status quo.

At the heart of the dispute is disagreement over how to draw the maritime boundary. Japan maintains the line should be based on the equidistant principle, or median line, between the countries’ coastlines. China argues for a boundary that reflects its extended continental shelf – a method that would push the line eastward and give it control of more undersea resources.