The planes superimposed over maps of China and Manchuria on this stunning man's undergarment are Mitsubishi "Nell", Naval Type 96 Attack Bombers G3M. First built in 1936, these land based long range bombers were obsolete by 1941. All Japanese military aircraft were nicknamed by the allies with men's or women's names during WWII to ease in identification and radio transmission. The Zero, Japan's formidable fighter plane, also made by Mitsubishi, was known as "Zeke".
In the dark blue bands are maps with roads, railway lines, and cities marked with tiny rising sun flags denoting their occupation by the Japanese.