The "Ara-kashi" (Quercus glauca) belongs to Fagaceae (the Beech family). It is a tall evergreen tree that is distributed from Miyagi-Ishikawa Prefecture of Honshu south to Shikoku and Kyushu in Japan, as well as Taiwan, Jeju Island of Korea, central and southern China and the Indo-China Peninsula. This tree grows in scrublands of mountains and fields, and up to a height of about 20 m. The leaves are obovate-oblong with large toothed edges at upper-half of leaf blades. The male clusters are descending at lower-half of new branches and the female clusters stand upright at the top, from April to May. The cupules have 6-7 circular layers. This timber is hard and used for making handles of farm implement. It is called "青剛櫟" in Taiwanese Chinese and "青岡" (qing gang) in Chinese.
In Korean, it is "jong-ga-si-na-mu" (종가시나무). This is a compound word formed from "jong-ga-si" (종가시) and "tree" (na-mu: 나무). The name derives from the fact that the cupules (acorns) of this tree are plump and rounded, resembling a bell (jong: 종), as well as from the fact that in the Jeju Island dialect, acorns were called "ga-si" (가시) or "ga-si-nang" (가시낭) in the Jeju Island dialect.