During the Tang Dynasty, Li Linfu, who was notoriously unlearned, was in charge of selecting officials. When reviewing a candidate named Yan Hui's written judgment, which contained the characters '杕杜' (dì dù), Li Linfu did not recognize the character '杕'. He mistakenly read it as '杖杜' (zhàng dù) and asked Wei Dou, a minister of the Ministry of Personnel, "What does '杖杜' mean here?" Wei Dou, knowing Li Linfu's ignorance but fearing his power, bowed his head and dared not reply.

On another occasion, when Jiang Du, a minor official in the Court of Imperial Sacrifices, had a son, Li Linfu personally wrote a congratulatory message. Instead of writing '弄璋之庆' (nòng zhāng zhī qìng), which means 'the joy of having a son' (where '璋' is a jade tablet given to a newborn boy), he mistakenly wrote '弄麞之庆' (nòng zhāng zhī qìng), using '麞' (roe deer) instead of '璋'. The guests who saw this covered their mouths to laugh, amused by his illiteracy.

This idiom later became a metaphor for people who make embarrassing mistakes in reading or writing characters due to their lack of scholarship.