The origins of Go are thought to be in ancient Asian history. People think that it is actually older than that. A more likely source for the origin of go lies in the way Zhou divination changed. The board is said to have started from an early form of the abacus. Others think it may have been a fortune-telling device, with the black and white stones representing yin and yang. A legend formed that it was made by an emperor to help improve the intelligence of his son. Recent archeology ventures have added more concrete facts to this. China is the probable birthplace of Go (Wei-chi or Weiqi in Chinese, meaning "surrounding game"), but the date of appearance is still uncertain. In old books, however, the ancient term yi is also used.