Sacrifices are the most important offering for sacrificial rites. During the pre-Qin period (the Zhou Dynasty in particular) it was only the emperors who were entitled to officiate at the sacrificial rites to the gods of heaven and earth or to imperial ancestors. The ritual practice of selecting animals for the sacrificial rites includes: (1) Animal selection, which is done three months before the day of the official ceremony according to the requirements for the horn and body, the color of hair, the sex and the size. (2) Animal raising, which means raising the selected animals in a very clean pen for three months. (3) Animal check-up, which is done thoroughly (again) on the eve of the day. (4) Animal greeting, which means that at the beginning of the official rites the emperor goes in person to greet and guide the animals to the site where the rites are going on. (5) Animal killing, which is done by the emperor ceremonially either shooting or slaughtering. And (6) animal sacrificing, which includes some parts of the ceremony like sacrificing the blood, the raw, and the cooked.
