Wang Xun, grandson of the renowned Eastern Jin chancellor Wang Dao, was a bold and brilliant young man known for his sharp mind and literary talent. At just twenty, he was appointed as a secretary by the Grand Marshal Huan Wen.
Once, to test Wang Xun's courage, Huan Wen rode a horse charging straight from the rear hall into the main assembly hall during a meeting at the Grand Marshal's residence. While other advisors panicked and scrambled to hide, some even crawling under tables, Wang Xun sat perfectly still, unshaken. Huan Wen reined in his horse, turned to survey the scene, and exclaimed, "One who can sit steady before a galloping horse will surely become a black-headed duke (a high official at a young age)!"
On another occasion, Huan Wen, seeking to test Wang Xun's literary talent, secretly had an attendant steal the draft of Wang Xun's speech during a council meeting. When Wang Xun discovered this, he remained completely unfazed. When it was his turn to speak, he delivered his address with such eloquence and fluency that it seemed to flow like a river. Huan Wen quietly took out Wang Xun's original draft to compare, and found that while the content was identical, not a single sentence matched the written version. Filled with admiration, Huan Wen was deeply impressed by Wang Xun's brilliance.
After getting to know Wang Xun over time, Huan Wen grew to trust him deeply. When leading his army on campaign, Huan Wen entrusted all military correspondence and administrative affairs to Wang Xun, whose competence earned him great respect from both civil and military officers in the camp.
Thanks to Huan Wen's appreciation and recognition, Wang Xun's official position was steadily promoted. He was granted the title of Marquis of Dongting and rose from Chief Clerk and Advisor to the Grand Marshal to Chief of the Central Army and Imperial Attendant.
One night in September 396 AD, during the Taiyuan era, the official Wang Xun dreamed that someone gifted him a giant brush as large as a roof beam. Waking with a strange certainty, he told his family, "I dreamed of a brush like a rafter—it seems some grand writing task awaits me."
Coincidentally, that very morning, the palace announced Emperor Xiaowu's sudden death. Because Wang Xun's literary talent was unmatched, the court ordered him to draft the mourning announcements, obituaries, and the emperor's posthumous title—a rare honor in Jin Dynasty history.
Later, the idiom "A Writing Brush as Big as a Rafter" came to praise renowned writers and their works, or to commend exceptional writing talent.
Source: *Book of Jin*, "Biography of Wang Xun"
Meaning of the Idiom: Later, the Chinese idiom "大笔如椽" came to describe praise renowned writers and their works, or to commend exceptional writing talent.