One spring, Guan Zhong and Xi Peng followed Huan Gong, King of the State of Qi, in an expedition against the State of Gu Zhu. The war didn't come to an end until winter. On their way back, they lost their way. Guan Zhong said:

Thereupon, they let several old horses lead in front and the army followed behind. Finally they found their way home.

"Old horses are wise animals who know their way. Let them lead the way for us!"

When the army entered the hills, they ran out of water. Then Xi Peng said:

Men of great learning like Guan Zhong and Xi Peng, when coming across difficulties, would also seek help from horses and ants of lower intelligence than human beings to find a way out.

"In winter, the ants stay on the south side of a hill, and in summer, on the north side. There is sure to be water source under their nest."

Thereupon, the soldiers exerted strenuous efforts to dig the ground. Sure enough, they found water under the ants' nest.