Feng Dao, a man of Jingcheng (modern Cangzhou, Hebei) during the Five Dynasties, styled himself "Kedao." He served ten rulers across four dynasties—Later Tang, Later Jin, Later Han, and Later Zhou—and was appointed prime minister three times. Known for his vast learning and eloquence, he had a calm and gentle nature.
He Ning, styled Chengji, was a man of Xuchang in the Han region of the Five Dynasties (present-day Dongping County, Shandong). He served as Chancellor under the Later Han and Later Zhou dynasties, known for his sharp intellect but also for his irritable and impatient nature.
One day, Feng Dao and He Ning were handling government affairs together in the Secretariat. Seeing Feng Dao in new clothes and new shoes, He Ning asked, "Lord Feng, how much did your new shoes cost?" Feng Dao slowly lifted his left foot and replied with a smile, "Not much, not much—only nine hundred coins."
He Ning, hearing this, quickly summoned his servant and scolded loudly, "Minister Feng bought new shoes for only nine hundred coins, while mine cost eighteen hundred. You useless fool, I can't trust you with anything. I'll deal with you when we return home."
Upon hearing this, the servant turned pale and trembled so violently that he dared not utter a single word.
Only then did Feng Dao clear his throat, slowly raise his right foot, and say loudly to He Ning, "Your Excellency He, I haven't finished yet. This right shoe also cost nine hundred coins. Added to the left one, doesn't that make exactly one thousand eight hundred coins?!"
The crowd could no longer hold back and burst into laughter. Amid the uproar, He Ning's face turned red and pale, at a loss. Later, the idiom "bursting into laughter" came to describe an entire room of people laughing at once.
Source: *Returning to the Fields Record*, "Feng Dao and He Ning"
Meaning of the Idiom: Later, the Chinese idiom "哄堂大笑" came to describe an entire room of people laughing at once.