Amanatsu (甘夏, ah-ma-na-tsu) is a yellowish orange citrus fruit, a group of cultivars of natsumikan (Citrus natsudaidai), which were discovered in 1740 in the Yamaguchi prefecture of Japan. Natsumikan is about the size of grapefruit and oblate in shape. The fruit contains 12 segments and about 30 seeds.