Guan Zhong and Xi Peng followed Duke Huan of Qi on a campaign against Guzhu. They set out in spring and came back in winter, and they lost their way. Guan Zhong said: “The wisdom of an old horse can be used.” They let an old horse go and followed it, and they found the road.
In the mountains there was no water. Xi Peng said that ants live on the sunny side of a mountain in winter and on the shady side in summer, and that water lies below an anthill. They dug and found water. Han Feizi comments: “Even the sage Guan Zhong and the wise Xi Peng did not find it hard to learn from an old horse and from ants.”
Lao ma shi tu, an old horse knows the way, describes an experienced person who knows the situation and can lead others.