The fourth-century a.d. Chronicles of Huayang, the oldest surviving Chinese geographical survey, records that Sichuan was once the domain of the Kingdom of Shu. According to these chronicles, one Shu king, who is described as having bulging eyes, taught his people how to cultivate silkworms, while another had the ability to communicate with fish. For thousands of years, the Kingdom of Shu was known only through such semilegendary accounts. Then, in 1927, a father and son dug a ditch at the site of three earthen mounds near the banks of the Yazi River in central Sichuan, 25 miles northeast of...