Emerging China is undoubtedly one of the biggest future security concerns for both Japan and the United States. The friction between China and Japan has recently grown, especially over territorial issues such as Senkaku Island. The United States also has disagreement with China over several issues such as human rights, Taiwan, Tibet, North Korea, and economic matters including currency and trade. The bilateral relationship between Japan and the United States will be instrumental for both countries to cope with China in the future. However, there is also friction within the Japan-U.S. alliance, and there are concerns within both countries. U.S. military bases in Okinawa have become a highly controversial issue in Japan, and Japanese criticism of the alliance has grown in recent years. In the United States, some opine that the United States should strengthen its bilateral economic relationship with China, signifying a diminution of the Japan-U.S. alliance.