evidence: Ties between China and Japan have been strained by a territorial row over a group of islands, known as the Senkaku islands in Japan and the Diaoyu islands in China. [...] China says that the islands have been part of its territory since ancient times, serving as important fishing grounds administered by the province of Taiwan. [...] The Senkaku/Diaoyu issue highlights the more robust attitude China has been taking to its territorial claims in both the East China Sea and the South China Sea. It poses worrying questions about regional security as China's military modernises amid the US "pivot" to Asia.