The day pillar for Tuesday, 15 June 2027

Day pillar	乙丑 (yi chou)
Heavenly stem	乙 (yi)
Earthly branch	丑 (chou)
Day element	Wood 木 (mu)
Polarity	Yin
Month pillar	丙午 (bing wu), governed by 芒种 (mangzhong)

Today's day pillar is 乙丑 (yi chou), a yin Wood day in the sixty-day cycle. The month pillar is 丙午 (bing wu), governed by the term 芒种 (mangzhong).

乙 (yi), the second heavenly stem

乙 is yin Wood: the vine and the grass, growth that gets where it is going by bending.

乙 is Wood in its yin form, and the classical image is deliberately small: creeper, flower stem, new grass. Where 甲 (jia) pushes straight through, 乙 goes around, and the tradition treats that as a different method rather than a weaker one.

It sits second among the ten stems, which is what makes it yin; the stems alternate yang, yin, yang, yin all the way down. That alternation is why 乙 can only ever pair with a yin branch, so 乙丑 (yi chou) exists in the sixty and 乙子 does not.

On a 乙 day the page names Wood as the day element and yin as the polarity. Two consecutive days can both read Wood, once as 甲 and once as 乙, which is the clearest way to see that element and polarity are two separate facts.