post-World War I depression; depression of 1920-1921
Historical term referring specifically to the economic depression that hit Japan after World War I, roughly 1920–1921.
The post-World War I depression hit the Japanese economy hard after the First World War.
Compound of 戦後 (postwar) and 恐慌 (panic, depression). The term is a historical label for the specific economic crisis after WWI.