By The South Asia Times

TOKYO - Japan has lodged a formal protest with China over the installation of a new structure in the East China Sea, calling the move a “unilateral resource development” in disputed waters, the Japanese Foreign Ministry said on Friday.

According to the ministry, Tokyo confirmed that China has installed the structure in waters near the Japan-China median line—an area where the two countries’ exclusive economic zones (EEZs) and continental shelf boundaries have yet to be formally demarcated, Kyodo News reported.

“It is extremely regrettable,” the ministry said in a statement, emphasizing that any unilateral development in the area undermines efforts to manage the dispute through dialogue and cooperation.

Japan also urged Beijing to resume talks aimed at implementing the 2008 bilateral agreement on joint resource development in the East China Sea, under which both sides committed to cooperation in areas of overlapping claims. Tokyo said China’s latest move contradicts the spirit of that accord.

This marks the second diplomatic protest Japan has lodged this month over Chinese resource development activities in the area, reflecting a sharp deterioration in bilateral relations. 

Beijing has yet to publicly respond to Tokyo’s latest protest.

Diplomatic Strain and Political Backdrop

Relations between Tokyo and Beijing have grown increasingly strained since Japanese Prime Minister Sanae Takaichi’s remarks in early November regarding a potential Taiwan contingency. China strongly objected to the comments, viewing them as interference in its internal affairs, and subsequently introduced a series of anti-Japanese economic measures, further souring ties.

The East China Sea has long been a source of friction between the two neighbors, particularly over energy exploration and the sovereignty dispute surrounding the Senkaku/Diaoyu Islands. Japan maintains that any development in areas of overlapping claims should be carried out jointly or through negotiations.

Regional Context: South China Sea Tensions

The dispute comes against the backdrop of escalating tensions across the wider Asia-Pacific, particularly in the South China Sea, where China has pursued expansive maritime claims that overlap with those of several Southeast Asian nations, including the Philippines, Vietnam, Malaysia, and Brunei.

In recent years, Beijing has constructed artificial islands, installed military facilities, and deployed coast guard and maritime militia vessels to assert control over contested waters. These actions have prompted repeated protests from regional states and heightened involvement by external powers such as the United States and Japan, which conduct freedom of navigation operations to challenge what they describe as excessive maritime claims.

Earlier this year, confrontations between Chinese and Philippine vessels near disputed reefs and shoals raised concerns about the risk of miscalculation in one of the world’s most strategically vital waterways, through which a significant portion of global trade passes.