The third enclosure of the traditional Chinese sky is the liveliest. The Heavenly Market Enclosure spreads across the region the Western charts assign to Ophiuchus, Serpens and Hercules, high in the evenings of summer, and it is drawn as exactly what its name says: a walled market city. Its asterisms include the offices a real market needed, the hall of trade standards, the celestial measures for grain and cloth, the shops of the jewellers and butchers, a tower from which the market is supervised. Around the whole district run two long walls of stars, and each star in the walls bears the name of a state of the Zhou world, Yan and Qi, Chu and Wei and their neighbours, so that the market stands enclosed by the realm's constituent countries the way a capital's market stood within the empire.
The scheme preserves a political geography that had already passed into history when the star map was finalised, which is one of the clues that the enclosures were codified in the early imperial period looking back at the Warring States world. Like the other enclosures, the market was watched for omens: activity among its stars was read against harvests, prices and the flow of goods. It is the most human district of the Chinese sky, a reminder that this astronomy modelled not just the throne but the whole life of the state, commerce included.