At first glance, Japan and the Philippines¡¯ decision to begin negotiations on a maritime boundary appears to be a routine exercise in international law. But China¡¯s unusually forceful response signals that the talks are about far more than drawing a line at sea.

Beijing argues the talks infringe on maritime rights it claims through Taiwan and sees discussions as part of a broader effort by two key U.S. allies to deepen strategic coordination in waters central to China¡¯s security interests.

When Prime Minister Sanae Takaichi and Philippine President Ferdinand Marcos Jr. used a late-May summit in Tokyo to launch the bilateral delimitation talks, China reacted swiftly.