Senkaku Islands dispute
According to the Chinese government, the relationship between China and Japan has been strained at times by Japan's refusal to acknowledge its wartime past to the satisfaction of China. However, according to the Japanese government, the expansion of People's Liberation Army and its assertive actions have been damaging the bilateral relation. Revisionist comments made by prominent Japanese officials and some Japanese history textbooks regarding the 1937 Nanking Massacre have been a focus of particular controversy. Sino-Japanese relations warmed considerably after Shinzō Abe became the Prime Minister of Japan in September 2006, and a joint historical study conducted by China and Japan released a report in 2010 which pointed toward a new consensus on the issue of Japanese war crimes. The Senkaku Islands dispute also resulted in a number of hostile encounters in the East China Sea, heated rhetoric, and riots in the People's Republic of China (PRC).