Tempura isn't Japanese.

This page is an interactive scrollytelling essay that needs JavaScript. The short version:

Tempura is Portuguese Catholic fasting food. Medieval Iberian kitchens fried battered vegetables on the four annual fasting weeks the Catholic church called quattuor tempora. Portuguese Jesuits brought the technique to Japan in 1543. When Japan closed its borders in 1639, the recipe stayed and the word — straight from Latin — became 天ぷら.

The other branch is fish and chips. Sephardic Jews living in Iberia for eight centuries cooked in the same kitchens and used the same batter to fry fish ahead of Shabbat. After their expulsion in 1492, they carried the technique to London. By 1860 an Ashkenazi shopkeeper named Joseph Malin paired the cold Sephardic fried fish with Belgian-style chips. Britain has been claiming it as a national dish ever since.

One Iberian kitchen. Two religions. Two diasporas. Two national dishes. Visit /explore for the full Meatball Atlas.