一蹴而就

Origin and story

The image of reaching a goal in one step is found in Su Xun’s Song-period letter Shang Tian Shumi Shu (上田樞密書). He observes that scholars would like to reach the realm of the sages in a single step, yet can fail even to produce a statement approaching the Way. He contrasts that aspiration with his own prolonged effort in studying the methods of earlier thinkers.

This is a metaphor in an argument about learning, not a Book of Song story about a task completed instantly. The later four-character idiom describes accomplishing something at once. It is especially common in negative statements that emphasize how much practice or sustained effort a goal requires.