In an essay on the bamboo paintings of Wen Yuke, the painter Wen Tong, Su Shi wrote: “So to paint bamboo, one must first have the finished bamboo in one’s chest. Take the brush and look closely, and when one sees what one wants to paint, rise quickly and follow it, moving the brush straight on to chase what one sees, like a hare leaping or a falcon diving. Let it go for a moment and it is gone.”
The Handian dictionary traces the idiom 胸有成竹, to have the finished bamboo in one’s chest, to this essay. It first meant having the whole image of the bamboo in mind before painting. Later it came to mean having made up one’s mind before acting.