Bone Weight Astrology (Cheng Gu Suan Ming) is a prediction method traditionally attributed to Yuan Tiangang, a master astrologer of the Tang Dynasty. Similar to the Four Pillars of Destiny (BaZi), it determines the fortunes, misfortunes, honor, and disgrace of a person's life with high accuracy, yet it is simpler to master. In this system, the year, month, day, and hour of birth are each assigned a specific numerical 'weight.' By summing these weights and consulting the 'Song of Bone Weight,' one can determine their lifelong destiny.
Yuan Tiangang was a renowned astronomer, astrologer, and diviner during the early Tang Dynasty, hailing from Chengdu (modern-day Sichuan). Active during the Sui-Tang transition, he served as a magistrate and was famous for his profound knowledge of metaphysics. He was particularly skilled in 'Wind Inspection' (divining via sound), physiognomy (face reading), and the Five Elements, making him a titan of metaphysics revered by both the Imperial Court and the common people.
His connection to Bone Weight Astrology rests on three pillars:
1. Foundational Philosophy: Yuan believed that a person's fate is linked to the cosmos and follows a specific 'numerical' logic. The concept of converting birth data into 'weight' is a simplified application of his theory that destiny can be quantified.
2. Attribution of Authority: While there is no direct historical evidence that Yuan penned the 'Song of Bone Weight,' later generations likely attributed the method to him due to his immense authority in the field. It serves as a simplified, folk-derivative of his complex theoretical systems.
3. Cultural Heritage: In Chinese folklore, many anonymous divination methods were ascribed to legendary figures like Yuan Tiangang to lend them credibility. Bone Weight Astrology, spread through oral tradition and manuscripts, became a key vehicle for preserving Yuan's legend in popular culture.