Treaty of Saint Petersburg signed between Japan and Russia

Background. The Treaty of Shimoda of 1855 had defined the border between Japan and Russia as the strait between Iturup (Etorofu) and Urup (Uruppu) islands in the Kurile chain, but had left the status of Sakhalin (Karafuto) open. Without well-defined borders, incidents between Russian and Japanese settlers began to occur. To remedy this situation, the Japanese government sent an ambassador, Enomoto Takeaki, to Saint Petersburg to clearly define the border in this area.

Terms. The treaty stipulated that Japan cede its portion of Sakhalin to Russia in exchange for the Kuril Islands. Consequently, Sakhalin became entirely Russian territory, while the entire Kuril archipelago became Japanese territory. Japan also secured compensation for residents, fishing access to the Sea of Okhotsk, and ten years of free port usage.

Legacy. The treaty remains part of a long-standing territorial dispute. Differences in translation contributed to controversy over the definition of the Kuril Islands. Japan renounced claims to the Kurils in 1951 via the Treaty of San Francisco, though the Soviet Union refused to sign, maintaining its claim as indisputable.