The Onion (Allium cepa) belongs to Liliaceae (the Lily family). It is a perennial herb that is probably native to the mountain rainge of Central Asia. This herb was cultivated in Ancient Egypt. It was introduced into Japan in Edo Era (1603-1868), and got down to cultivate in Meiji Era (1868-1912). It begins to grow in spring, and in summer it becomes edible with spherical bulbs. The varieties can be divided into two breeds, bitter onion group from East Europe and sweet onion group from South Europe. Most of the onions cultivated in Japan are bitter onions.