Many treasures lay buried underground in Luoyang City during the Song Dynasty (960–1279). They had been buried by people before that dynasty. When a house was sold, the buyer had to pay an extra digging fee if the grounds in the premises had never been dug up.
Left Premier Zhang Guan bought a mansion in Luoyang for a few million qian. The deal had almost gone through when the seller suddenly demanded a large digging fee of one million qian.
