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.

Have you read the story of Panko breadcrumbs?

It came from food and fuel shortages in WW2 where the ingredients for bread but no ovens or equipment to cook it into anything. One guy hooked a bunch of dough up to a car battery and electrocuted it and created a crustless loaf with a weird texture. He also discovered this weird texture made for great even sized crumbs with a uniform colour and after the war ended decided to turn it into a business.