Core Terminology

The Tang dynasty was a crucial period for the systematization of metaphysical terminology. The 'Four Pillars' — the year, month, day, and hour columns — became established, marking the basic formation of the Bazi fortune-telling technique that arranges a destiny chart from birth time. Li Xuzhong is considered the central figure of this transformation; he used the three pillars (year, month, day) of stems and branches to calculate destiny, and was later revered as the founding ancestor of Bazi metaphysics. The prosperity and openness of the Tang provided fertile ground for the development of numerology; the imperial examination system stimulated scholarly attention to the question of fate, while the flourishing of Buddhism and Daoism infused metaphysics with rich religious and philosophical resources. Na Yin Five Elements was widely applied to life-destiny calculation during this period, forming a complex year-destiny system.

Key Figures

Li Xuzhong — an official during Emperor Xianzong's reign; according to Han Yu's 'Epitaph for Li Xuzhong,' he used the stems and branches of a person's birth year, month, and day to predict longevity, honor, and disgrace with uncanny accuracy, and is regarded as the founder of Bazi metaphysics; Monk Yixing — a Tang-dynasty eminent monk and astronomer who presided over the compilation of the Dayan calendar, whose astronomical and calendrical achievements indirectly promoted the precision of metaphysical calculation

Important Works

Li Xuzhong Mingshu — attributed to Guiguzi with commentary by Li Xuzhong, systematically discusses the life-destiny method using the year pillar as primary and three pillars for calculation, containing extensive Na Yin Five Elements and spirit-noble judgments; Dayan Calendar — the new calendar created by Yixing, improving the precision of solar-term and transition-moment calculations, providing a more reliable calendrical basis for metaphysical month-pillar calculation

Historical Significance

The germination of the Four Pillars concept and the maturation of the three-pillar fortune-telling method enabled metaphysics to differentiate itself from broad astrology and divination, forming a unique technical approach that calculates personal destiny exclusively from birth time. The Na Yin fortune-telling tradition and the year-destiny methodology established in the Tang provided direct technical preparation for the rise of Ziping technique in the Song.