Wikipedia says 73 million in 1940. For Germany it says 69,3 million in 1939 and almost exactly 70 million, but apparently without the annexed populations of Austria and Sudetenland, which I estimate at about 10 million or more.
Edit: not sure whether to include the population of Korea into Japan’s statistics, which would make Japan more populous than Germany with certainty. The 73 million figure is without Korea.
Meh. Japan does seem like it was higher, according to projections. (http://www.wolframalpha.com/input/?i=country+populations+1939)
Wikipedia says 73 million in 1940. For Germany it says 69,3 million in 1939 and almost exactly 70 million, but apparently without the annexed populations of Austria and Sudetenland, which I estimate at about 10 million or more.
Edit: not sure whether to include the population of Korea into Japan’s statistics, which would make Japan more populous than Germany with certainty. The 73 million figure is without Korea.