The mountains in southern Yunnan teemed with precious stones. However, they were too high and steep for people to climb directly.
To obtain the gems, the local people repeatedly shot at the monkeys living on the mountaintops using catapults.
Enraged by the attacks—and being irascible and vengeful by nature—the monkeys retaliated by gathering in groups and hurling stones down the mountainside.
The people collected these stones of various sizes. After discarding the ordinary ones, what remained were the superior precious stones.