During the Spring and Autumn period, a man named Sun Yang lived in the state of Qin. Legend has it that he was the most famous horse judge in ancient China—able to tell at a glance whether a horse was exceptional, especially if it could cover a thousand li in a single day. People revered him as a god. Since the celestial deity in charge of horses was called Bole, everyone simply called Sun Yang "Bole."
According to legend, the master horse appraiser Bole compiled his expertise into a manual titled *The Classic of Horse Judging*, where he listed the traits of exceptional horses and included illustrations for comparison.
Bole, a legendary horse expert, had a son of mediocre intelligence but lofty ambitions. After reading his father's classic *The Art of Judging Horses*, the son thought finding a thousand-li steed would be easy and set off to find one. He returned with a toad, proudly declaring, "Father, I've found a horse with a bulging forehead and bright eyes—just as you described!" Bole sighed, "This 'horse' loves to jump but cannot run." The idiom "Bole's son" now mocks those who blindly follow rules without understanding the essence.
He saw that the *Xiangma Jing* (Horse Appraisal Manual) stated the main features of a thousand-li horse were a high forehead, large eyes, and hooves like stacked wine yeast cakes, so he took the book and went out, wanting to test his own eye for talent.
After walking a short distance, he spotted a large toad with a bulging forehead and big eyes. Muttering to himself, "This matches the description of a fine horse perfectly—I'll catch it and show Father," he grabbed the toad and brought it home. Presenting it to Bole, he said, "Father, I've found an excellent horse! It's just like the one in your book *The Art of Judging Horses*, except the hooves don't quite match." Bole looked at the toad in his son's hand, torn between amusement and frustration, and replied with dry humor, "Well, it does look a bit like one—but there's no way to ride it!" The idiom "Searching for a Steed by a Picture" originally describes seeking a fine horse by following an image, now used to mean following clues blindly or acting mechanically and rigidly.
Source: *Chaoye Hezai*
Meaning of the Idiom: Later, the Chinese idiom "按图索骥" came to describe how blindly following rules without understanding the essence leads to absurdity.