During the ninety years from 1855 to 1945, a cataclysmic struggle took place for control of Northeast Asia. At stake was a vast area encompassing the Korean peninsula, the Manchurian plain with its surrounding mountains, the Mongolian plateau and an enormous tract of eastern Siberia stretching from Lake Baikal to the island of Sakhalin and the Sea of Japan. The first sign of Japanese political involvement in the region came in 1892–1893, when Captain Fukushima Yasumasa led a reconnaissance mission to Siberia, the Russian Far East, Mongolia and Manchuria. In the tangled and violent politics of post-Tsarist Siberia, Japan had many contending parties it could choose from as local allies, but it chose a strategy of alliance with the anti-Bolshevik Whites, and a subsidiary strategy of cultivating the national aspirations of the indigenous peoples.