What is Oracle Bone Inscriptions? Why did people write on tortoise shell bones at that time?

1. The so-called Oracle Bone Inscriptions is an ancient writing engraved on tortoise shells and animal bones, which is a kind of "recorded writing" just like the "knotting notes" of ancient ancestors.

2. During the Shang Dynasty, divination prevailed, and nobles had to divine everything. Divination is predicting bad luck. The method is to drill holes in tortoise shells or animal bones and bake them with fire, and predict bad luck through the shape and direction of cracks after cracking, and engrave the prediction results on them for later inspection.