I always forget the word for “citrus” in Japanese: 柑橘類 (kankitsurui). Not like it’s a really difficult word, but try putting them on a table and distinguish them in a test. All citrus is native to Asia, and Kumamoto in particular is famous for it, so much so that Sawako, my wife, frequently brings citrus home that I can’t identify. “What is that?” I ask, and she answers, “Some kind of citrus.” (She doesn’t know either.) Here’s a guide. - William