Wang Liang's disciple claimed he could travel a thousand li in a day with his team of horses pulling the chariot. However, Zao Fu's disciple doubted this was possible.
Wang Liang's disciple questioned, "The two outer horses are swift steeds capable of a thousand li a day. The two horses in the middle are also fine horses that can cover the same distance. How is it that I cannot travel a thousand li in a day?"
Zao Fu's disciple replied, "It is precisely because your reins are too long. That is why you will never achieve a thousand li in a day."