Oracle Bone script (pinyin: Jia3gu3wen2) are incised characters found on ox scapula and tortoise plastrons (oracle bones) thought to be the earliest Chinese characters.
The diviner would inscribe on the bone or shell his name, the current date of the sexigesimal cycle and then inscribe two possible outcomes on the shell. Depending on how the fired object cracked, diviners would interpret the answer from them. For example:
"Tomorrow it will rain"
"Tomorrow it will not rain"
The outcome was then inscribed on the bone and saved. The inscriptions are known as jiaguwen (甲骨文) or oracle bone inscriptions.