The Qianzaodu ËëóºÓø has been very well preserved and is one of the most significant works in the Yiwei æ¶êÕ. It has also been one of the biggest influences on the later development of the study of the Zhouyi ñ²æ¶ (a.k.a. Yijing æ¶Ìè [Book of Changes]). Based on the previous scholarship, we further explore the critical points of the Yijing in the Qianzaodu, including the meaning of yi æ¶, the notion of sitai ÞÌ÷¼, the notion of guaqi ÎÏÑ¨, the notion of jiugong ÎúÏà, and the notion of yaochen ý¡òã. The discussion of yi addresses the three kinds of yi. Sitai refers to Taiyi ÷¼æ¶, Taichu ÷¼ôø, Taishi ÷¼ã·, and Taisu ÷¼áÈ. Guaqi refers to the guaqi of the Eight Hexagrams in Qianzaodu. Jiugong explains the notion that Taiyi takes its number by operating jiugong. Yaochen refers to the understanding that the Sixty-four Hexagrams and the twelve Earthly Branches are closely intertwined.