一字千金

Etymology
When Lu Buwei wrote Lushi Chunqiu, he presented the finished book at the gate of Hanyang and offered a thousand taels to anyone who could correct even one character.

Idiom

 * 1) extraordinary writing; uncommonly good writing

Noun

 * 1)  a word of great value
 * 2) very good handwriting or calligraphy
 * 3) incomparable kind favor