Enter the ken-po goku-i, the key to the ancient practices assimilated into Okinawan culture and customs where three also signifies the three pairs of starts in the Norther Bushel which resides over men's heads recording their acts and passing judgment as to which is detected, i.e. goodness or wickedness. Then there is the three spirits of the recumbent body residing in man, the spirit, the mind, and the body.
Lastly we see the three poisons of human heart, greed, anger, and stupidity. The very essence of understanding as to the Tao is its three things of Heaven, Earth and Man which is symbolized in the I Ching symbols that transcend all the classics in one form or the other. These three are considered the coordinate powers.