The day pillar for Tuesday, 18 August 2026

Day pillar	甲子 (jia zi)
Heavenly stem	甲 (jia)
Earthly branch	子 (zi)
Day element	Wood 木 (mu)
Polarity	Yang
Month pillar	丙申 (bing shen), governed by 立秋 (liqiu)

Today's day pillar is 甲子 (jia zi), a yang Wood day in the sixty-day cycle. The month pillar is 丙申 (bing shen), governed by the term 立秋 (liqiu).

甲 (jia), the first heavenly stem

甲 is yang Wood: not the garden but the trunk, the growth that has already decided which way is up.

甲 is the first of the ten heavenly stems, and the tradition reads it as the tall tree, timber standing rather than timber cut. Its element is Wood and its polarity is yang, which in BaZi means the outward, expansive form of that element rather than the softer one.

Being first is structural, not a ranking. 甲 opens the sexagenary count, so 甲子 (jia zi) is day one of the sixty, and every sixty days the calendar comes back to it. Stems run in a fixed order and never skip, so 甲 turns up once every ten days without fail.

You meet 甲 as the top character of the day pillar and as the day element on the page. Anyone born on a 甲 day carries 甲 as their day master, which is a fact about their chart, not a forecast about their week.