Japanese decision for war in 1941
While the Empire of Japan was largely committed to forcible expansion by the late 1930s, specific plans, decisions and preliminary operations (e.g. French Indochina), by the Empire of Japan, were made to begin large-scale operations of World War Two in the Pacific in December 1941, primarily in 1941 but some in 1940. These wre more detailed than broad strategic directions such as the Strike-North and Strike-South Movements, or a decision to consolidate in China and Manchuria.
Operations in French Indochina, taken in 1940, were transitional, in that they directly bore on the Second Sino-Japanese War, but also would establish bases for Strike-South. Strike-North had largely been rejected due to the rough handling of Japanese troops, by Soviet forces, on the border, including such things as the Nomohan Incident.