From the First Sino-Japanese War in the 1890s, "Hokushin-ron" came to dominate Japanese foreign policy. It guided both the Japanese invasion of Taiwan (1895) and the Japan–Korea Treaty of 1910 which annexed Korea to Japan. After the Russo-Japanese War (1904-5) Field Marshal Prince Yamagata Aritomo, a political and military ideological architect of "Hokushin-ron", traced the lines of a defensive strategy against Russia. A February 1907 Imperial National Defence guideline envisioned two strategies: "Nanshu Hokushin Ron" (南守北進, defence in the South and advance in the North) and "Hokushu Nanshin Ron" (北守南進, defence in the North and advance in the South). There was intense discourse within Japan on the two diverging theories. Following World War I, Japanese troops were deployed as part of the Siberian Intervention during the Allied intervention in the Russian Civil War, with the hope that Japan could be freed from any future Russian threat by detaching Siberia and forming an independent buffer state. The Japanese troops remained until 1922, encouraging discussion by Japanese strategic planners of the idea of permanent Japanese occupation of Siberia east of Lake Baikal.