noun
Japan–Soviet Union; Japanese–Soviet
Historical term used in contexts such as diplomacy, trade, and war, referring to relations between Japan and the Soviet Union (now Russia). Commonly seen in compounds like 日ソ共同宣言 (Japan–Soviet Joint Declaration).
日ソ共同宣言は1956年に調印された。
The Japan–Soviet Joint Declaration was signed in 1956.
日ソ漁業交渉が行われた。
Japan–Soviet fishery negotiations were held.
Refers to Japan–Russia relations, used for both historical and modern contexts. 日ソ is specifically for the Soviet period (1922–1991).
Abbreviation of 日本 (Japan) and ソ連 (Soviet Union), using the first character of each. The reading にっソ comes from 日 (にち) + ソ, with gemination.