In the quiet of a Peking University research room, shelves groan under the weight of 60 thick volumes. Key points and original sources are listed below.

• In the quiet of a Peking University research room, shelves groan under the weight of 60 thick volumes. Stacked, they stand taller than an average human. Inside their pages lie the details of more than 23,000 ancient Chinese bronze vessels, weapons, chariot fit...S1

• In the quiet of a Peking University research room, shelves groan under the weight of 60 thick volumes. Stacked, theyS2