"A courtyard as crowded as a marketplace" describes a gate or courtyard bustling with people.
During the Warring States Period, Zou Ji, the prime minister of Qi, was tall and handsome. To persuade King Qiwei to welcome honest criticism, he shared this story:
One morning, after dressing for court, Zou Ji looked in the mirror and asked his wife, "Who is more handsome, Mr. Xu from the north city or I?"
"You are, of course. How can Mr. Xu compare with you?" she replied.
Mr. Xu was renowned for his looks. Doubting his wife's words, Zou Ji asked his beloved concubine the same question. "How can Mr. Xu compare with you?" she answered.
The next day, a guest visited. Zou Ji posed the question again, and the guest said, "How could Mr. Xu be more handsome than you?"
A few days later, Mr. Xu himself visited. Zou Ji carefully observed him and concluded he was not as handsome as Mr. Xu.
He then told King Qiwei, "I am not actually more handsome than Mr. Xu, but my wife, concubine, and guest all said I was. My wife is partial to me, my concubine fears me, and my guest seeks my favor—so they all flattered me. In Qi, your courtiers are partial to you, your officials fear you, and your subjects seek your favor. You must have even more flatterers and be more deceived than I! Our state is vast with many cities. You meet more people than I do, so the deception must be greater. If you sincerely seek honest advice, it would greatly benefit our state."
The king agreed. He issued a decree: first-class reward for those who criticized him to his face; second-class for written criticisms; third-class for public criticisms. As expected, people flocked to the palace to offer their opinions. The area before the palace gate became as busy as a marketplace.