孺子可教 — “A young person who is promising and capable of being taught or guided”

Zhang Liang, courtesy name Zifang, was originally a nobleman from the state of Han. After an unsuccessful assassination attempt on Qin Shihuang, he fled and hid in Xiapi, changing his name to Zhang Liang.

One day, Zhang Liang was strolling on Yishui Bridge near Xiapi when he encountered an old man dressed in brown. The old man's shoe had fallen beneath the bridge. Seeing Zhang Liang approach, he called out, "Hey, young man! Go pick up my shoe for me!"

Zhang Liang was annoyed, but seeing the man's advanced age, he went down and retrieved the shoe. The old man then said, "Come! Put it on for me!"

Zhang Liang was very displeased but thought that since he had already picked up the shoe, there was no point in refusing. So, he respectfully put the shoe on for the old man. The old man stood up, said nothing by way of thanks, and turned to leave.

Zhang Liang stared blankly at the old man's retreating figure, guessing that he must be an extraordinary person. Sure enough, after walking a short distance, the old man returned and said, "You, young man, show great promise and are worthy of my instruction. Five days from now, in the morning, please come to the bridge to see me." Zhang Liang quickly agreed.

Five days later, Zhang Liang rushed to the bridge in the morning. The old man had already arrived and said angrily, "When meeting an elder, you should arrive early. In another five days, come earlier to see me!"

Another five days passed. Zhang Liang woke up early and hurried to the bridge, but unexpectedly, the old man had already arrived again. The old man said, "You are late again. Come back in five days."

Yet another five days went by. Zhang Liang was determined to arrive earlier than the old man this time. So, just after midnight, he made his way to the bridge in the dark to wait. As dawn broke, he saw the old man slowly making his way onto the bridge and quickly went forward to help him. Only then did the old man say happily, "Young man, this is how it should be!"

As the old man spoke, he took out a copy of "Tai Gong's Art of War" and handed it to Zhang Liang, saying, "You must diligently study this book. Once you have thoroughly understood it, you can become an emperor's teacher."

After Zhang Liang thanked the old man, the old man walked away leisurely. Later, Zhang Liang's study of "Tai Gong's Art of War" was highly successful, and he became an important strategist under Liu Bang, Emperor Gaozu of Han, making significant contributions to the establishment of the Han Dynasty.