Geng (庚) — Yang Metal

Geng is yang metal, classically the war-axe and the autumn frost (劍戟之金). It severs what cannot remain, executes the harvest, ends one cycle to allow the next. Geng Day Masters carry an air of sharpness and decisive action — natural law-enforcers, soldiers, judges, surgeons. They prefer truth over pleasantness and respect strength.

Geng pairs with 乙 in 乙庚合化金 — yang metal courted by yin wood, the soft tempering hard. Geng requires fire to refine it into a tool (火煉真金) and water to wash off rust; Geng without fire stays raw iron, never becoming a precise instrument.