Tokyo's propensity for getting into territorial and maritime boundary disputes with its neighbors seems large. And if the disputes with China escalate any further, they could make the recent confrontation with South Korea over the Takeshima islets (Dokdo in Korean) look tame.
Tokyo insists that the median or equidistance line between the Ryukyu Islands (Okinawa) and the Chinese mainland is the boundary of its exclusive economic zone (EEZ) in the East China Sea. But Beijing says the continental shelf should be the basis for deciding the EEZ boundary. This shelf extends all the way to the Okinawa Trough, or well within the EEZ claimed by Japan. As a compromise Beijing calls for joint undersea development in the disputed area, until rival boundary claims have been settled.
However, Tokyo claims sole right to develop potential oil and gas reserves within its claimed EEZ. It objects even to a Chinese gas development on the Chinese side of that claimed EEZ, on the grounds that gas could be leaking from Japan's claimed EEZ area. Gunboats are threatened when it senses any challenge to its claimed rights.