Under the rules of occupation in 1945, Japan was ordered to comply with US/Allied restrictions: War is illegal for Japan to engage in; other than self defense.
That is why the Armed Forces of Japan are now called "SELF DEFENSE FORCES."
Actually it is simply a NAME CHANGE; The Self Defense Air Force can still fight; the Self Defense Ground Force can still fight; and the Maritime Self Defense Force has warships. Added to the NAME CHANGE is Japan's Law (Ordered by the Occupation Forces): These Forces CANNOT engage in "Combat" (other than in self-defense); such as Operation Desert Storm in January to February 1991. Japan could send NON-COMBAT units to Iraq, but not Fighter Planes, tanks, Infantrymen, and Warships.
They could send Engineer Units, Medical Units, Administrative Support Units, Transportation Units, etc.
These restrictions were similar to that applied to Germany after WW1. Germany was not allowed a Large Army, Air Force, or Navy (especially submarines). Only enough armed forces to defend themselves. However, history has shown that Germany got around these restrictions, as they did re-arm and end up fighting in WW2.
Thirty-Second Army - Japan - was created in 1944.
Army War College - Japan - ended in 1945.
Fifty-Fifth Army - Japan - was created in 1945.
With Japan's industrial base; Japan built a navy, army, and air force. After building those forces; their navy, army, and air force trained for war.
Yes, Japan does have a military but has no army. Japan's military can only be used for self-defense and the reason why Japan does not have an army because they'll be bringing military weapons and vehicles to attack other countries. After WW2, they were banned by the rules. Japan can only use its military in defense.
Third Army - Japan - was created in 1904.
Third Army - Japan - ended in 1945.
Sixth Army - Japan - ended in 1945.
Sixth Army - Japan - was created in 1939.
Sixteenth Army - Japan - ended in 1945.
Sixteenth Army - Japan - was created in 1941.
Eleventh Army - Japan - was created in 1938.
Eleventh Army - Japan - ended in 1945.
Fiftieth Army - Japan - ended in 1945.
Fiftieth Army - Japan - was created in 1945.
Taiwan Army of Japan was created in 1919.
Fortieth Army - Japan - was created in 1945.