  Having a Ready Formed Plan 胸有成竹

  In the Song Dynasty, an artist called Wen Tong 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. 
  宋朝画家文同，特别喜欢画竹子。他在园子里种了许多竹子，经常仔细观察竹子的生长过程，特别是在晴天，雨后以及春夏秋冬不同的季节下竹子的各种形态，对竹子有了较深切的了解。一旦到他提别绘画时，他的胸中早已有了竹子的形象，所以总是能够把竹子画得生动逼真，活灵活现。

  This idiom is used to indicate having a well thought out plan already before one sets out to do something, making success assured.
  "胸有成竹"用来比喻在做事情以前，已经有了充分成熟的考虑，因而成功的把握很大。