What does it mean that the ancient jade turtle shell has a round hole?

In ancient times, there were round holes in the shell of jade turtles, which were mainly used to tie ropes. The ropes passed between the opposite round holes to fix the carapace and the abdominal armor.

In ancient China, the tortoise was a god beast. The ancient people were afraid of heaven and earth, and could not grasp their personal destiny and the future of the whole clan, so they often used tortoise divination for good or ill luck.