The natsumikan (Citrus natsudaidai) is Japan's big, bracing "summer orange" — a thick-rinded, pomelo-type citrus, roughly grapefruit-sized and deep yellow-orange, whose juicy segments eat sharply sour-sweet with a clean, slightly bitter edge. Ripening on the tree through winter but left to hang and mellow until early summer, it is eaten fresh out of hand, its coarse rind is boiled into marmalade and candied peel, and its refreshing tartness makes it one of the most distinctive of the traditional Japanese citrus.