In the 1945 prewar period, Naichi has an estimated population of 72,000,000.
Mainland Japan (, naichi, lit. "inner lands") is a term to distinguish the area of Japan from its outlying territories. Per the Statistics Bureau of the Ministry of Internal Affairs and Communications, the population distribution of Japan proper from 1920 to 1945 is as follows 1940-10-01 73,114,308 1945-11-01 71,998,104 The Empire of Japan entered World War II in September 27, 1940, by signing the Tripartite Pact with Germany and Italy, though, it wasn't until the attack on Pearl Harbor on December 7, 1941, that the US entered the conflict. 
