前事不忘，后事之师 — “Past events, if not forgotten, serve as a guide for future ones”

In 379 BC, Duke Yin Qi of the State of Qi ascended the throne and became known as King Qi Wei. During the initial years of his reign, King Qi Wei neglected state affairs, indulging in drinking and festivities. Consequently, the state gradually declined, and its people faced hardship.

One day, a man named Zou Ji arrived, claiming to be skilled in understanding the zither (qin). Knowing King Wei's love for music, he sought an audience. King Wei welcomed him and presented him with a zither. However, Zou Ji merely stroked the strings without playing.

Puzzled, King Wei asked, "Sir, why do you only touch the strings but not play? Is the zither not good?" Zou Ji set aside the instrument and gravely replied, "Your humble servant understands the principles of the zither. As for playing it, that is the task of musicians." He then proceeded to elaborate at length on the theory of the zither.

King Wei grew impatient, interrupting him to say, "Since you understand the principles so well, you must be skilled at playing. I wish you would perform a piece for me." Zou Ji responded, "Your humble servant makes the study of zither principles his profession, so naturally, he is skilled at playing. Your Majesty's duty is to govern the state; how could you not be skilled in state affairs? Now, Your Majesty occupies the throne but neglects the governance of the state. How is this different from your humble servant merely stroking the zither strings without playing? If I only stroke the strings and do not play, I cannot fulfill Your Majesty's wishes. If Your Majesty sits on the throne but does not attend to state affairs, I fear you cannot fulfill the wishes of your people!"

King Wei was greatly startled. "Sir," he said, "you have used the analogy of playing the zither to advise me. I now understand your profound intention!" He then kept Zou Ji by his side to discuss important state matters. Zou Ji counselled King Wei to curb his drinking, stay away from distractions, prioritize practical matters, distinguish between loyal and treacherous officials, care for the populace, strengthen military preparedness, and build a powerful state. With the principle that 'past events, if not forgotten, serve as a guide for future ones,' King Wei was deeply convinced and immediately appointed Zou Ji as his Prime Minister.