, it was a bit of both Samurai and Third Reich influence... The early designs by Ralph were certainly inspired by Samurai and Bedouin, as were the sketches by Joe. But
, there is a well-documented case of when a couple of guys were in a prop room and put on a WWII German steel helm and gas-mask and that played a HUGE part in it. But I'd say it's more of an homage to Kurosawa than Nazis though.
And the Imperial Navy uniforms borrow heavily from WWII Imperial Japan uniforms more than the Nazis. Caps and cut of the uniforms especially, but it's Nazi-esqe for sure.