The Group of Seven's Ise-Shima gathering in Mie Prefecture last month was the summit that fell in the woods, generating few global headlines. For China, though, it was a geopolitical game-changer that could reverberate loudly through the world economy in the months ahead.

Buried in the middle of typically bland G-7 economic assessments and cooperation pledges was a pointed warning over maritime provocations. "We are concerned about the situation in the East and South China Seas, and emphasize the fundamental importance of peaceful management and settlement of disputes," the May 27 communique said. "We reaffirm the importance of states' making and clarifying their claims based on international law, refraining from unilateral actions which could increase tensions and not using force or coercion in trying to drive their claims."

While it didn't mention China specifically, Asia's biggest economy was written between the lines in bold typeface. The word "reaffirm," meanwhile, is typical G-7 passive aggression. In Beijing's reading, this is an escalation of efforts to contain its rise — and do Tokyo's bidding in the process. China's anger is partly about timing, as we're just months away from a potentially explosive ruling that will probably go against China by an international court in The Hague.