During the Spring and Autumn period, Sun Yang, who was Duke Mu of Qin's horse expert, was exceptionally skilled at observing and judging the quality of horses. People praised him by calling him 'Bole,' after the mythical star deity who managed celestial horses. Any horse he deemed excellent would immediately increase in value.

Once, someone took a horse to the market to sell, but for three days, no one showed any interest. The owner then invited Bole to take a look at it. Immediately, someone bought the horse at a high price.