Diplomatic relations were established between the USSR and Japan on Feb. 25, 1925. A convention on the basic principles governing relations was signed prior to this date, on Jan. 1, 1925. Both countries agreed to respect the principle of nonintervention in internal affairs and to refrain from any hostile acts. The USSR agreed to respect the Treaty of Portsmouth of 1905, although it pointed out in a special declaration that the Soviet government did not share any political responsibility for its conclusion. All other treaties signed between Russia and Japan prior to Nov. 7, 1917, were to be reexamined. Soviet sovereignty over northern Sakhalin was restored, and the Soviet government agreed to grant concessions to Japanese nationals for the exploitation of natural resources that were on Soviet territory.
By the terms of the fishing convention of Jan. 23, 1928, Japanese nationals obtained the right to catch and process all types of fish and marine products, aside from fur seals and sea otters, in the Soviet littoral of the Sea of Japan, the Sea of Okhotsk, and the Bering Sea. Japanese nationals could lease fishing grounds both at sea and along the littoral. This convention was repeatedly renewed, but a number of limitations were introduced owing to repeated violations of its conditions by the Japanese.
Attempts by Japanese militarists to carry out aggressive policies were repelled, and a neutrality pact was concluded on Apr. 13, 1941. Nevertheless, the Japanese repeatedly violated the agreements and refused to fulfill their obligation undertaken in the spring of 1941 to close their concessions in northern Sakhalin (Soviet demands were met only in 1944). They also maintained an army along the Soviet border, which immobilized the Soviet troops stationed there, and thus assisted fascist Germany. On Apr. 5, 1945, the Soviet government denounced the 1941 pact, and when the Japanese government rejected the demand of the Soviet allies of the anti-Hitler coalition for unconditional surrender, the Soviet Union declared war on Japan on Aug. 8, 1945. Japan suffered a military defeat and signed the act of unconditional capitulation on Sept. 2, 1945. According to a decision of the Yalta Conference of 1945, southern Sakhalin was returned to the Soviet Union and the Kuril Islands were transferred to the USSR. The Soviet Union refused to sign the Treaty of San Francisco of 1951 with Japan, since it had been drawn up in the atmosphere of the cold war by the USA and Great Britain in defiance of the Declaration of Potsdam of 1945 and other Allied agreements.
On May 14, 1956, the USSR and Japan signed agreements on cooperation in the rescue of victims of shipwrecks and on open sea fishing in the northwest Pacific. Both agreements were to become operative on the effective date of the peace treaty or at the resumption of diplomatic relations. The joint declaration of Oct. 19, 1956, put an end to the state of war between the USSR and Japan and restored diplomatic and consular relations. The USSR abandoned its claims to reparations from Japan and agreed to transfer to Japan the islands of Habomai and Shikotan with the stipulation that these islands will be transferred in fact to Japan after the conclusion of a treaty of peace. The USSR also expressed its willingness to support Japan’s request for admission to the UN.
Ties between the countries were expanded by the trade treaty of Dec. 6, 1957 and by agreements on establishing a regular shipping line between Nakhodka and Yokohama (June 3, 1958) on air transportation (Jan. 21, 1966), on exchange of consumer goods between Japan and the Soviet Far East for 1966–70 (Jan. 21, 1966), on a consular convention (July 29, 1966), on scientific and technical cooperation in the fishing industry (July 14, 1967), and on cooperation in radio and television broadcasting (Feb. 8, 1968).
In a joint declaration of Oct. 10, 1973, both countries noted the favorable development of relations and agreed to increase economic cooperation, particularly in those areas related to the development of natural resources in Siberia, and to increase their contacts with regard to environmental protection. On the same date, agreements were signed on such matters as scientific and technical cooperation, on the exchange of graduate students and researchers, and on the exchange of official publications.
The two countries signed agreements for the purchase of Japanese machinery, equipment, vessels, building materials, and consumer goods for cooperation in coal production, prospecting for gas in Yakutia, and the exploitation of forest resources in the Far East. These agreements included a protocol on the granting of a long-term credit for $1.05 billion to the USSR (Apr. 22, 1974) and a credit agreement for $450 million (June 26, 1974). A general agreement was concluded for 20 years (July 26, 1974) for Soviet deliveries of coal from southern Yakutia and Japanese deliveries of machinery, materials, and other goods.
The countries signed a protocol on cooperation in television (Dec. 13, 1974) and agreements on geological prospecting work and oil and gas extraction on the Sakhalin Island shelf (Jan. 28, 1975), on fishing in the open sea along the Japanese littoral (June 7, 1975), on conditions for loans for financing additional prospecting for Yakut gas and for purchase of four ammonia plants from Japan (protocols of July 15, 1975), and on cooperation in television and radio broadcasting (July 24, 1975).