Lingqijing (or Ling Ch'i Ching; 靈棋經 lit.
It is not known when, nor by whom, it was written, though a legend has spread that strategist Zhang Liang received the book from Huang Shigong (黃石公), a semi-mythological figure in Chinese history.
The first commented edition of the work appeared in the Jin Dynasty.
As its name suggests, the work concerns "divining" with tokens, such as Chinese chess (xiangqi i.e.象棋) pieces (instead of with the more traditional turtle shells or yarrow stalks used in I Ching divination).
Four have the character for "up" (上, pronounced shang), four have the character for "middle" (中, zhong), and four have the character for "down" (下, xia), representing respectively the Three Realms: Heaven (天, tian), Humanity (人, ren), and Earth (地, di).