During the Three Kingdoms period, the renowned Eastern Wu general Gan Ning, known for his wisdom and courage, had already distinguished himself in the Battle of Red Cliffs. He then followed Commander-in-Chief Zhou Yu in a relentless pursuit of the enemy all the way to Nanjun.
Cao Ren, a Wei general defending Nan Commandery, defeated Wu's vanguard Jiang Qin by waiting at ease for the exhausted enemy. When Zhou Yu heard this, he flew into a rage and mustered his troops for a decisive battle. Gan Ning stepped forward to advise, "Attack Yiling first, then take Nan Commandery." Zhou Yu nodded, calling the plan brilliant, and ordered Gan Ning to lead the assault on Yiling.
Gan Ning led his troops in a fierce battle against Wei general Cao Hong at Yiling, capturing the city and forcing Cao Hong to flee to Nanjun. With only a few hundred soldiers at first, Gan Ning recruited more after entering the city, bringing his force to nearly a thousand.
That evening, Cao Ren sent Cao Chun and Niu Jin with over five thousand troops to completely surround Yiling. The Cao forces launched repeated assaults on the city, but each time the Wu army fought them back.
The next day, Wei forces piled up earth to build a high tower, from which they rained arrows down into the city, killing many Wu soldiers. The troops were terrified, but Gan Ning alone remained calm, laughing and chatting as if nothing unusual were happening.
Gan Ning ordered his men to gather the arrows scattered on the city walls, then selected his best archers to return fire against the Wei forces. Though the Wei army outnumbered them several times over, Gan Ning held his ground with steady composure, preventing the enemy from breaking through. Days later, Zhou Yu arrived with reinforcements, and together they launched a pincer attack that drove back Cao Hong, Cao Chun, and Niu Jin. Zhou Yu personally visited the garrison to commend the defenders, recording Gan Ning's achievement as a meritorious deed.
Later, people used the idiom "talking and laughing as usual" to describe staying cheerful and composed in unusual circumstances, just as one normally would.
Source: *Records of the Three Kingdoms*, "Book of Wu: Biography of Gan Ning"
Meaning of the Idiom: Later, the Chinese idiom "谈笑自若" came to describe staying cheerful and composed in unusual circumstances, just as one normally would.