This paper argues that Japan fought a three-front war prior to 1941. Japan not only fought China in the Second Sino-Japanese War, but conducted military operations against the Soviet Union. The third front occurred within Japan, as military factionalism prevented Japan from focusing on either China or the Soviet Union. By 1941, weakened through years of war, Japan focused their attention on French Indochina. This ultimately led to U.S entry into World War II.
"Japan's War on Three Fronts Prior to 1941,"
Bound Away: The Liberty Journal of History: Vol. 3
, Article 2.
Available at: https://digitalcommons.liberty.edu/ljh/vol3/iss1/2