The sky and the earth were at first one blurred entity like an egg. Pangu was born into it. The separation of the sky and the earth took eighteen thousand years-the yang which was light and pure rose to become the sky, and the yin which was heavy and murky sank to form the earth. Between them was Pangu, who went through nine changes every day, his wisdom greater than that of the sky and his ability greater than that of the earth. Every day the sky rose ten feet higher, the earth became ten feet thicker, and Pangu grew ten feet taller. Another eighteen thousand years passed, and there was an extremely high sky, an extremely thick earth, and an extremely tall Pangu. Then came the Three Emperors(1).

So these numbers came into existence and evolve like this. The numb or begins with one, becomes established at three, is completed at five, prospers at seven, and ends in nine. So the sky is ninety thousand li(2) from the earth.