Mikan
Japanese mandarins
みかん
Citrus unshiu
Japanese mandarins (Citrus unshiu) are officially called Onshu mikan ("Honey citrus of Wenzhou") or Satsuma (after one of the main production areas in southern Kyushu). Different from "our" mandarin oranges (clementines, tangerines), which in Japan are called ponkan (Citrus reticulata). Wenzhou in China was famous for its mikan, but the name seems to have been added in the Meiji-period more for literary reasons to the Japanese mikan than to indicate a real link with Wenzhou.
There was, however, a link with China. The mikan originates in S.E. Asia and came to Japan via China. In the 16th c. we find the Kishu mikan in Wakayama, an area which had trade relations with China. This type contains seeds and has since been superseded by the seedless Onshu mikan. The Onshu mikan was found in the early 17th c. in Nagashima in Kagoshima Prefecture ("Satsuma"), a domain which had trade relations with China via the Ryukyu islands (Okinawa). Samurai were not interested in mikan growing so it lasted until the late 19th century until mikan started to be grown in earnest - and then it took off with a vengeance.
Mikan are seedless and easy to peel as the skin is only lightly attached. Flesh is delicate and sweet. The fruit is soft and therefore easily bruised. It is the archetypal winter fruit (the first mikan appear in early October). Reminds Japanese of the kotatsu! Consumed in vast quantities. Three or four mikan a day provide all the necessary Vitamin C.
[Mikan in Wakayaama Pref.]
The mikan is very cold-tolerant and it is interesting when hiking through the fields in winter in Japan to see trees loaded with these small oranges!
Most important production centers: Wakayama (185,400 tonnes, 17% of total); Ehime (168,300 tonnes, 16% of total); and Shizuoka (146,200 tonnes, 14% of total).
Japanese Food Dictionary