The white grape variety is cultivated in Japan, but the origin is unknown. Synonyms are Kochiou, Konshu, Koshiou, Koshiourebe and Koushuu. It is named after the former province Kōshū, which roughly coincides with the current Yamanashi Prefecture. According to one hypothesis, it supposedly reached China from Europe via the Silk Road as early as the 8th century and was introduced to Japan by Buddhist monks. According to another hypothesis, it was discovered by a certain Amemiyas Kageyu around 1186 in the south of the Kofu Valley at the foot of Fujiyama. According to DNA analyses carried out in 2006, it is a species of Vitis vinifera, which makes the hypotheses unlikely. There is a close relationship to the variety Koshu Sanjaku. Koshu was a cross-breeding partner of the new varieties Koshu Sémillon and Komahikari.