Yuanbao jingzhuan 元包經傳 "Classic and commentary of the primordial bud", shortly called Yuanbao 元包, is a divination book written during the Northern Zhou period 北周 (557-581) by Wei Yuansong 衛元嵩. The original title was Yuanbaojing 元包經 or Yi yuanbao 易元包. The Tang-period 唐 (618-907) scholars Su Yuanming 蘇源明 (d. c. 764) and Li Jiang 李江 wrote commentaries on it that became an integral part of the book, so that it is often referred to with the title jingzhuan "classic (Wei's original) and commentary (by Su and Li)". In this shape the book has a length of 5 juan. A phonetic commentary was written by the Song-period 宋 (960-1279) scholar Wei Hanqing 韋漢卿. All editions of the Yuanbao include a 2-juan-long appendix called Yuanbao shu zongyi 元包數總義 "Overall meaning of the numbers in the Yuanbao" that was written by Zhang Xingcheng 張行成 during the Southern Song period.
Wei Yuansong hailed from Chengdu 成都 (modern Chengdu, Sichuan) and was an expert in calendric calculations based on the theory of Yin and Yang. For his book he was rewarded the title of seal-holding (chijie 持節) Commandery Duke of Shu 蜀郡公. The Ming-period 明 (1368-1644) scholar Hu Yinglin 胡應麟 (1551—1602) says that Wei had also written a book called Qi sanjiao lun 齊三教論. The bibliography Chongwen zongmu 崇文總目 and the two encyclopedias Tongzhi 通志 and Wenxian tongkao 通考 erroneously call Wei a Tang-period person.
According to the text, the Five Agents (wuxing 五行) were the "essence of Yin and Yang and the source of each creation" (yinyang zhi jingqi, zaohua zhi benyuan 陰陽之精氣，造化之本源). In the sky, the Five Provesses were visible as the five planets, on earth as the five sacred mountains (wuyue 五嶽), and in the human world in the five talents (wucai 五材) and the five virtues (wude 五德). They controlled all processes in the world among the ten thousand beings, and balanced all changes from one aggregate status to another, or one appearance to another shape. They also controlled colours, sounds, tastes, shapes and words. The human body, his nose, heart, and will were determined by the Five Agents and only thus able to be fit for life. The Five Agents were therefore the basis to become a "perfect man" (zhiren 至人) without any evils, errors, or misfortune. The perfect man did not need to prognosticate the future, like the common man.
The ideas in the Yuanbao were influenced by Yang Xiong's 揚雄 (53 BCE-18 CE) divination book Taixuanjing 太玄經 from the Han period 漢 (206 BCE-220 CE), while the arrangement follows the largely lost divination book Guicang 歸藏, in which the hexagram Kun 坤 headed the divinatory symbols, followed by Qian 乾, Dui 兌, Gen 艮, Li 離, Kan 坎, Xun 巽, and Zhen 震. The order known from the famous divination book Yijing 易經 is Qian, Kun, Kan, Li, Zhen, Gen, Xun, and Dui.
The Yuanbao operates with eight changes after which the original hexagram is reached again. It also includes explanatory parts called ciwen 辭文. The text is not easy to understand because Wei Yuansong uses a lot of substitution terms in order to avoid tabooed characters (like those of deceased emperors). The different layers of commentaries are geared to the structure of the Taixuanjing.
The commentary by Zhang Xingcheng is not an explanatory part of the text, but a commentary in its proper sense, in which he rectifies errors made by Su Yuanming and Li Jiang. He also describes the general idea behind the book in order to bring the hexagrams and their interpretation into a whole concept. His Yuanbao shu zongyi has also been published separately.