老生常谈 — “A truism”

The idiom "Lao Sheng Chang Tan" (老生常谈) originates from the “Records of the Three Kingdoms, Wei Shu, Biography of Guan Lu.” It refers to the kind of words an old scholar often says, which lack new ideas and are heard so frequently they become tiresome.

The story goes that during the Three Kingdoms period, there was a man named Guan Lu, who was diligent and intelligent from a young age, particularly fond of astronomy. By the age of fifteen, he had mastered the 'I Ching' and divination, gradually gaining a reputation. His fame eventually reached the Minister of Personnel, He Yan, and the Imperial Attendant, Deng Yang.

One day, on the twenty-eighth day of the twelfth lunar month, these two high-ranking officials, bored after a meal, summoned Guan Lu to divine for them. Guan Lu knew that He Yan and Deng Yang were close associates of Cao Shuang, Cao Cao's grandnephew, and were notorious for abusing their power. After some thought, he decided to use this opportunity to teach them a lesson and diminish their arrogance.

Upon seeing Guan Lu, He Yan loudly demanded, "I hear your divination is very accurate. Quickly, tell me if I will have another chance to get promoted and acquire wealth. Also, I've been dreaming of flies constantly landing on my nose these past few nights; what does that omen mean?"

Guan Lu paused, then said, "In ancient times, Duke Zhou was loyal and upright, assisting King Cheng in establishing the nation, bringing peace and prosperity. Now, your position is even higher than Duke Zhou's, yet few are grateful to you, while many fear you. This is probably not a good omen. Your dream, according to divination, also indicates misfortune!"

Guan Lu continued, "To turn ill fortune into good and avert disaster, you must emulate great sages like Duke Zhou, cultivate good intentions, and perform good deeds." Deng Yang, listening from the side, was unimpressed. He shook his head repeatedly and said, "These are just 'Lao Sheng Chang Tan' (old scholar's usual talk), meaningless."

He Yan's face turned ashen, and he remained silent. Seeing this, Guan Lu laughed heartily and said, "Although these are 'Lao Sheng Chang Tan' remarks, they should not be taken lightly!"

Soon after the New Year, news arrived that He Yan, Deng Yang, and Cao Shuang had been executed for conspiracy. Upon hearing this, Guan Lu repeatedly remarked, "They disregarded the 'Lao Sheng Chang Tan,' so it's no wonder they met such a fate!"