The Hall of Imperial Zenith was the Vault of Heaven of the Altar of Praying for Bumper Crops. The tablet of the God of Heaven and the tablets of the emperor’s ancestors to be displayed and worshipped during the ceremony held in the Hall of Prayer for Good Harvests were kept here. On the day before the ceremony, the emperor came here in person to burn incense sticks and perform the divine greetings for the transference, and then the officials of the Court of Imperial Sacrifices transferred the tablets to their appropriate places in the Hall of Prayer for Good Harvests. With a wudian roof (five-ridged hip roof) covered with blue glazed tiles, the hall was first built in the 18th year of Emperor Yongle’s reign (1420).