Heavenly Stem Combinations: From Hetu-Luoshu to Astronomical Conjectures
Heavenly Stem Five Combinations are one of the most foundational yet enigmatic doctrines in Chinese metaphysics. This article takes readers through the math of Hetu, the astronomical correspondences, and various schools’ conjectures to show how the doctrine reflects a cosmic rhythm.

Chapter 6: Wu-Gui Combining into Fire
Wu is old Yang Earth, like a dam or mountain. Gui is deepest Yin Water, like rain or dew. Earth overcomes Water—so why Fire$9
Conjecture 1: Geothermal Gui water penetrates deep Wu earth, meets geothermal heat, turns into steam—fire energy erupts, like a volcano or hot spring.
Conjecture 2: Thunderstorm Lightning Wu is the cloud (Earth energy), Gui the rain. When they meet in a summer thunderstorm, their clash produces lightning—fire.
Conjecture 3: Physiology Wu corresponds to the stomach, Gui to the kidneys. Earth overcomes Water yet needs Fire (Heart fire) to regulate digestion; the Wu-Gui combination thus symbolizes the Kidney water nourishing the Heart fire.