Protesters try to cross a police line during an anti-Japan protest in Shenzhen, south China's Guangdong province August 19, 2012. Several Japanese nationalists landed on Sunday on a rocky island in the East China Sea at the heart of a territorial row with Beijing, sparking protests in several Chinese cities and a diplomatic rebuke from Beijing. Tokyo and Beijing have been feuding for decades over the island chain, known as the Senkaku in Japan and the Diaoyu in China, near potentially huge maritime gas fields. REUTERS/Tyrone Siu (CHINA - Tags: POLITICS CIVIL UNREST)