Chinese Idiom 胸有成竹（xiōng yǒu chéng zhú）

In the Song Dynasty (sòng cháo 宋朝), an artist called Wen Tong (wén tóng 文同) was especially fond of drawing bamboos. He planted a lot of bamboos in his garden so that he could observe the process of their growth and appearance in different seasons. He knew bamboos so well that whenever he took up the paintbrush he already had a picture in his mind, and thus he could always paint bamboos in a vivid and lively way. bulaiya.com