AP Photo

A SMALL fish like Taiwan, diplomatically isolated as it is, does not often pick a fight with both of Asia’s largest economies at the same time. But this disputed island chain, known to Japan as the Senkaku islands and to China as the Diaoyus, is casting its strange spell across the whole of the East China Sea. A fierce shootout with water-cannon broke out between Japan’s coast guard and Taiwan’s on the morning of September 25th. The Japanese side was trying to repel an armada of almost 60 Taiwanese fishing vessels, which had sailed irritatingly near the islets, by blasting some of them with deck-mounted water cannon. Taiwan’s patrol boats retaliated by firing back with their own high-pressure hoses at the Japanese coastguard ships, all the while booming over...