Japan's new prime minister has pledged to stand firm against China on the issue of disputed East China Sea islands claimed by both sides.This morning Tokyo summoned China's ambassador to protest about regular incursions by Chinese government vessels into the islands' waters, which China was told to cease.In Beijing, the Chinese government rejected Japanese demands that it stop sending ships to the waters of disputed East China Sea islands; incursions that Japan considers a violation of its territory. Spokesman Hong Lei was speaking on the same day that Japan's new nationalist government under Shinzo Abe summoned the Chinese ambassador in Tokyo to strongly protest against the presence of Chinese ships; the latest exchange in what experts see as an increasingly dangerous dispute. The islands at the center of the row are known as the Senkaku to Japan which governs them, and the Diaoyu to China which also claims them. Although nobody lives on them, the issue of who exercises sovereignty over them has blighted bilateral ties for decades. Anger at Japan for its conduct in the Second World War and denial of wrongdoing since runs deep in China. When Japan nationalized three of the islands in September furious protests erupted across the nation. Since then China has been sending a constant stream of marine surveillance and fisheries administration vessels to the islands’ waters to proclaim its sovereignty, where Japan’s coastguard has confronted them. In mid-December China sent a marine surveillance plane for the first time in place of its ships. Japan responded by scrambling fighter jets; the first time military craft have been deployed in the arena. Similar mid-air confrontations have been taking place since. Experts fear that if Japan acts because China ignores its protests, or if accidentally colliding aircraft cause a fatality, the situation will escalate. Given nationalist public opinion on both sides, neither will be able to back down. While politicians on both sides say worsening the quarrel would benefit nobody, China’s state controlled media has warned of a war that could drag in the US. Some members of the public say they are ready. A gathering storm, then, over the East China Sea.