The Imperial Japanese Army was organized into several types of Armies:

Territorial Armies

• The General Defense Command was responsible for Japan, Korea and Formosa.
  • Japan Defense Army was responsible for Japan - contained over 2 million men in 55 divisions, plus numerous separate units by August 1945.
    • Northern Army - Hokkaido and northern Honshu
    • Eastern Army - Eastern Honshu and Tokyo
    • Middle Army - Central Honshu
    • Western Army - southern Honshu, Shikoku Island, and the Ryukyu Islands to include Okinawa.
  • Formosan Army - Responsible for Formosa now called Taiwan.
  • Korean Army - responsible for Korea.

• Kwantung Army - Manchuria
• China Expeditionary Army - China
• Southern Army - also called the Southern Area Army, responsible for southern China and South East Asia
• 5 Air Armies of the Imperial Japanese Army Air Service

Field Armies

• Groups of Armies - territoral organizations equivelant to western Theaters of War
• Areas Armies - Equal to western field Armies. There is still much confusion between numbered Area Armies and Armies, some being referred to in IJA records by both terms.
• Armies- equal to western Corps
  • First Army
  • Second Army
  • Third Army
  • Fourth Army
  • Fifth Army
  • Eleventh Army
  • Twelfth Army
  • Fourteenth Army
  • Fifteenth Army
  • Sixteenth Army
  • Seventeenth Army
  • Nineteenth Army
  • Twenty-Third Army
  • Twenty-Fifth Army
  • Thirty-Second Army - Okinawa
  • Thirty-Fourth Army
• Special Mission Forces

Auxiliaries

• Indian National Army
• Burmese National Army
• Kempeitai