The placard (see photo above) used by the dumb, right-wing japs actually argues against their cause and supports China/Taiwan's claim over the Diaoyu Islands.
"1895" refers to the (unequal) Treaty of Shimonoseki of 1895 between the Qing government of China and the Meiji government of Japan after the former's devastating defeat in the first Sino-Japanese War (1894-95). Under the terms of the treaty, Japan took possession of Taiwan and Diaoyu Islands from China, and the Qing government gave up its suzerainty over Chaoxian (Chosun) Korea.
When Japan unconditionally surrendered to the Allied powers at the end of World War II in 1945, it agreed to give up all territories taken between 1895 and 1945, the period of Japanese imperialism. Thus, Taiwan was returned to the Republic of China, and Korea became independent (and split into two different countries). Even by the dumb jap right wingers' own logic, Diaoyu, therefore, legally and rightfully belongs to the Chinese nation...