Square division

A square division is a designation given to the way divisions are organized. In a square organization, the division's main body is composed of four regimental elements. Since a regiment could be split into separate battallions for tactical purposes, the natural division within a division would be to have two regiments bound together as a brigade.

Imperial Japanese Army Divisions were organized as square divisions prior to 1938 when they began to form triangular divisions during the Second Sino-Japanese War.

United States Army divisions were organized as square Divisions prior to World War II. Since World War II, the U.S. Army has gone with a triangular division, where combined arms doctrine has all but abolished regimental purpose, and now defines a brigade as three battalions.