As I understand it, it was created by a hotel chef trying to find something to feed foreigners (mostly soldiers) very soon after the war, so it’s kinda different.

Tempura and Pan (bread) come from the Portuguese. They did start growing hot peppers like many after they got here via either the Portuguese and/or Dutch following the Columbian Exchange.

Much like there’s American Chinese food, there’s also Japanese Chinese suited to their tastes. Pizza is probably the most prominent examples: mayo, corn, etc. pizza is common here.