The student of Wang Liang said he could go a thousand li a day with his horses pulling the chariot. But the student of Wang Liang questioned, "The two horses on the side are swift horses that can go a thousand li a day. And the two horses in the middle can also go a thousand li a day. How come I can not go a thousand li a day?" "It is because your rein of the horses are too long, so you can never go a thousand li a day."

王良的弟子说自己用这几匹马赶车可以日行千里。造父的弟子却认为他不可能做到这一点。王良的弟子质问说：“我这两边的马，是一天能跑一千里的马，中间的两匹役马，也是一天能走一千里的好马。怎么可能一天走不了一千里路呢？”造父的弟子说：“就因为你把马的缰绳系得太长了，所以，你绝对走不了一千里路。”