Yi Chou Day Pillar (乙丑)

Quick answer: 乙丑 is yin wood (乙) sitting on earth (丑, the Ox). The stem sits on its wealth star (偏财 Indirect Wealth), at the Decline life stage; its Na Yin is 海中金 (Gold in the Sea).

When your day pillar is 乙丑 (Yi Chou), your Day Master is 乙 — yin wood — and it sits on 丑, the Ox. 乙丑 is number 2 of the sixty pillars. Below we unpack the stem, the branch, the hidden stems, the element balance and the traditional readings, with links to the deeper guides.

The stem: 乙 Yi

The classical description of 乙 comes from the Di Tian Sui (滴天髓):

乙木雖柔，刲羊解牛，懷丁抱丙，跨雞乘猴，虛濕之地，騎馬亦憂，籐蘿繫甲，可春可秋。

“Yi wood, though soft, can cut the Goat and loosen the Ox. Holding Ding and embracing Bing, it can ride the Rooster and mount the Monkey. On damp and empty ground, even riding the Horse brings worry. A vine tied to Jia does well in spring and in autumn.”

— Di Tian Sui (Drops from Heaven’s Marrow) 《滴天髓》, 天干論. Original text: Wikisource · also on ctext.org (different edition). Translation: bazimethod.

Yi (乙) is yin wood: grass, flowers, vines. The Di Tian Sui says it can “cut” a goat and “untie” an ox and survives by bending and climbing — adaptable wood rather than rigid wood. On the day pillar, this stem is the Day Master — the “self” of the chart that every other character is measured against. The full verse and a ten-gods table are on the Yi Wood Day Master page.

The branch: 丑 Chou

Chou (丑), the Ox, is cold, wet winter earth at the end of the year. It is the storehouse of metal and holds 己, 癸 and 辛. The day branch is traditionally called the spouse palace (夫妻宮), the seat closest to the self, so readers look at it for themes of partnership and private life. As a month it corresponds to the 丑 month (early January to early February, the end of winter).

How the stem and branch work together

The stem controls the branch’s element, so 乙 sits on its own wealth. For a man’s chart, classical texts treat wealth as the spouse star, so “wife on the wealth seat” is a frequently quoted image. More generally, the seat is read as practical and resource-minded, provided the stem is strong enough to handle what it sits on.

In the life-stage cycle this is Decline: past the peak, still with some substance. It is a weak-to-moderate footing on its own.

Hidden stems in 丑

Each branch contains one to three hidden stems. Measured against 乙, they take these ten-god roles:

The main qi, 己, is Indirect Wealth (偏财) — the element the Day Master controls, same polarity; windfalls and wide dealings in the traditional reading. The middle qi, 癸, is an Indirect Resource (偏印) — the element that produces the Day Master, same polarity; unconventional learning and support. The residual qi, 辛, is Seven Killings (七杀) — the element that controls the Day Master, same polarity; pressure, challenge and drive. The main qi carries most weight; the minor stems become important when another stem in the chart “draws them out”, for example when the same stem appears openly in the month or hour pillar.

Element balance

Counting the stem plus the hidden stems (weighting the main qi fully and the minor qi less, one common convention), the pillar leans wood > earth > water > metal, and fire is absent from the pillar itself. That does not mean the chart lacks it — the year, month and hour pillars usually change the picture entirely, and the month branch matters most of all.

Because the strength of 乙 depends above all on the month of birth, the same 乙丑 day reads very differently in different seasons: a wood Day Master is strongest in spring and weakest in autumn. The five elements and useful god guides explain how practitioners decide whether a chart wants more of an element or less.

Na Yin: 海中金

In the older Na Yin system the sixty pillars are grouped in pairs, each with a poetic “sound element”. 乙丑 and 甲子 share 海中金, “Gold in the Sea”, a metal image. Note that the Na Yin element (Metal) is separate from the elements of the stem (Wood) and branch (Earth); most modern Zi Ping readers use Na Yin as colour rather than as the basis of the reading.

Traditional personality themes

Popular Bazi writing associates 乙 Day Masters with quiet resilience and a talent for finding a way round, and sometimes with flexibility, diplomacy and persistence. On a 丑 seat, the 偏财 (Indirect Wealth) star in the spouse palace colours that picture, as described above. These are traditional images, offered for cultural interest. They are not evidence about any real person, and a single pillar never decides a reading — the classics always judge the whole chart, its season and its balance.

Clashes, combinations and void branches

丑 clashes with 未 and forms a six-combination (六合) with 子, said to produce earth. It also belongs to the 巳酉丑 three-harmony group of metal. When those branches appear in the year, month or hour, or arrive in a luck pillar, tradition says the spouse palace is “moved”. See combinations and clashes.

The pillar belongs to the 甲子 decade (旬) of the sixty-cycle, whose two “void” branches (旬空, 空亡) are 戌 and 亥. Many practitioners note when those branches appear elsewhere in the chart or in luck pillars, reading them as weakened or “empty”.

A closer look at 乙丑

乙丑 is the pillar the Di Tian Sui almost names outright. Its verse on 乙 says soft wood can still “cut the goat and untie the ox” (刲羊解牛): 未 is the goat and 丑 is the ox, so this day pillar is the second half of that line made literal. Commentators read it as yin wood surviving on earth branches by working its roots in, not by force.

The catch is that 丑 gives 乙 almost no root of its own. None of its hidden stems is wood: 己 is Indirect Wealth, 癸 is Indirect Resource, and 辛 is Seven Killings. The ox is the storehouse of metal, so the branch quietly holds the one element that cuts 乙. If 巳 and 酉 also appear in the chart, the 巳酉丑 metal trine can form and that pressure becomes a theme of the whole chart, not a hidden detail.

丑 is also wet, frozen soil from the coldest month. In the climate-adjustment (調候) approach of the Qiong Tong Bao Jian, wood born in the cold months looks first for 丙 fire to warm it, so readers check whether the sun appears anywhere in an 乙丑 chart. A 未 branch clashes the ox and, by tradition, “opens” the metal storehouse. The 癸 inside does help a little: it is damp water that feeds the wood slowly.

Find your own day pillar

The day pillar cannot be worked out from the Western date alone — it follows an unbroken sixty-day cycle, and a birth after 23:00 may count as the next day in some schools. Enter your birth data in the free Bazi calculator to see yours, then read the chart-reading guide.

Previous in the cycle: 甲子 Jia Zi · Next: 丙寅 Bing Yin · All 60 day pillars

Keep learning

More in Day pillars, plus core guides — or go back to the Bazi calculator home page.

Classical quotations are copied from the public-domain texts on Wikisource; links let you check every line. English translations are our own. Traditional Bazi statements are reported as tradition, not as fact.