having had the images of the bamboo ready in one's bosom
In the song Dynasty (960-1279), there was a scholar whose name was Wen Tong and who styled himself Yuke. He was not only admired by others for his great learning, but also enjoyed widespread renown for his bamboo drawing. Every day there were always quite a few peoply who called at his house to ask for one of his bamboo drawings.
Actually, Wen Tong loved bamboos so much that he had grown various bamboos everywhere around his house. No matter what season it was and no matter whether it was sunny or rainy, he used to go to the bamboo forest to observe how they were growing. He pondered over the lenght and breadth of the bamboo poles as well as the shapes and colours of the leaves. Whenever he had gained a new understanding, he went back to his study, spread a piece of paper and prepareed some ink by rubbing an ink stick on an ink slab, and drew what was in his mind on the paper. Through accumulation over a long period of time, the images of the bamboo in different seasons, under different weather conditions and at different moments were deeply imprinted in his mind. So whenever he stood before the paper and picked up a painting brush with concentrated attention, the various forms of the bamboo which he had observed at ordinary times at once rose before his eyes. And so every time he was drawing bamboos he appeared confident and at ease, and all the bamboos he had painted were very vivid and true to lift.
When people spoke highly of his paintings, he always said modestly that he had just put the images of the bamboo imprinted in his mind on the paper.
A young man wanted to learn bamboo drawing; when he knew that Chao Buzhi had made a profound study of Wen Tong's art of drawing, he went to Chao Buzhi for instruction. Chao Buzhi wrote a poem to him. In the poem, there are the following two lines:
When Yuke was painting the bamboos,
He bad their images ready in his bosom.
Later people have summarized the lines as "having had the images of the bamboo ready in one's bosom," which means having had ready plans or designs in one's mind before doing a certain job so that its success is guaranteed. It is also used go mean being calm and cool - headed in dealing with things.
This story comes from an article writted by Su Shi concerning Wen Yuke's art of bamboo drawing.