The most popular citrus fruit in Japan is the satsuma tangerine, a type of mandarin orange. It is easily peeled with the fingers, and the sac membranes are relatively tough, so it can be eaten without getting the hands wet with the juice.
It is an early winter fruit, and is especially popular during the New Year season. One pictures a family sitting at leisure around a kotatsu (a covered table with a heat source under it) chatting and watching TV while eating satsumas from a bowl set on the middle of the table.
Satsumas are also grown in China, where they may have originated, and several other places, but in Europe they are mainly grown in Spain, and in North America, in Florida and other Gulf states. Sometimes, from the season, they are called “Christmas oranges.”
However, in Japan if you go to a store and ask for “satsuma,” don’t be surprised if you a shown to the sweet potatoes, satsuma-imo. In Japan satsuma are called mikan. Satsuma is a region of southern Kyushu, and it is not even particularly known for growing the fruit. It is said it was the wife of a US minister to Japan who gave them the name “satsuma” in 1878.