At the beginning of the 20th century, Russia and Japan could not reach a lasting compromise over Korea. Several rounds of diplomacy for Korean neutrality or spheres of influence did not result in any lasting agreement. Due to the mutual suspicion and opportunistic searches for expansion into Korea and Manchuria, they could not reach an enduring understanding on Korea. Korea also could not play a role as an independent buffer state due to its own weakness. In conjunction with Japan’s consistent efforts to establish an exclusive control over the whole of Korea, war broke out in 1904 and Korea became a protectorate of Japan. The developments in the Far East at the beginning of the 20th century hold implications on current northeast Asian security as well.