王者所以祭秉何? 緣事父以事天也。

祭天必以祖配何? 自內出者，無匹不行，自外至者，無主不止。故推其始祖，配以賓主，順天意也。

五帝、三王祭天，一用夏正何? 夏正得天之數也。天地交，萬物通，始終之正。故《易乾鑿度》云"三王之郊，一用夏正"也。

祭天必在郊何? 天體至清，故祭必於郊，取其清潔也。

祭日用丁與辛何? 先甲三日，辛也; 後甲三日，丁也，皆可以接事昊天之日。故《春秋傳》郊以正月上辛日。《尚書》曰:"丁巳，用牲于郊，牛二。"

祭天歲一何? 言天至尊至質，事之不敢褻瀆，故因歲之陽氣始達而祭之也。

祭天作樂者何? 為降神也。

《周官》，祭天后夫人不與者，以其婦人無外事 。

The Suburb Sacrifice (Lu, 1a-b; Ch'ên, 12. 1a-4b).

The King sacrifices to Heaven according to the same principle as he served his father.

At the sacrifice the first ancestor must be associated with Heaven.

The Five Emperors and the Three Kings all used the first month of the Hsia calendar for the sacrifice to Heaven (Ch' ien tso tu).

The sacrifice to Heaven must take place in the 'suburb' chiao 郊 ¹.

The day for the sacrifice is either a ting-day or a hsin-day (Ch'unch'iu chuan; Shang shu).

The sacrifice takes place once a year--so as not to be too intimate with Heaven--at a time when the yang-fluid begins to reassert itself.

At the sacrifice music is performed.

The Queen is not allowed to take part in the sacrifice (Chou kuan).