Yi Wood Day Master (乙): the Yin Wood stem in BaZi
Last checked · verse from the Di Tian Sui on Chinese Wikisource; tables calculated
乙 (Yi) is the second Heavenly Stem, the yin partner of 甲 Jia in wood. The Di Tian Sui opens its verse with "Yi wood, though soft, can cut the Goat and carve the Ox", and its annotation describes Yi as the wood of branches and leaves.
Stem
乙 Yi
Element and polarity
Yin Wood
Combines with
庚 Geng (Metal)
Clashes with
辛 Xin
The Yi verse in the Di Tian Sui (滴天髓)
Verse traditionally attributed to Jingtu (京圖), with the annotation attributed to Liu Ji (劉基, Ming dynasty); quoted from Chinese Wikisource. The translation is ours.
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 carve the Ox. Holding Ding and embracing Bing, it can ride the Rooster and mount the Monkey. On empty, damp ground, even riding the Horse brings worry. A vine tied to Jia does well in spring and in autumn.
The verse uses human words (kind, loyal, filial) for how the stems act on one another in a chart; it does not describe people.
What the annotation says
The Goat and the Ox are 未 and 丑, yin earth that even soft Yi can master. With a single Bing or Ding, Yi is not afraid in the Monkey (申) or Rooster (酉) months. Born in the Rat month (子) with Xin, Ren or Gui showing, even a Horse (午) helps little, since one fire cannot stand against much water. With plenty of Jia or 寅 it is a vine on a tall tree, at ease in spring and in autumn.
The annotation opens with 「乙為枝葉之木」 (the wood of branches and leaves). Summarized in our words from the annotation on the same 天干論 page on Wikisource.
Wood in the Huainanzi (淮南子)
The Huainanzi, 天文訓 chapter, lists each direction with its element, season, planet and animal, and ends with the two stems of its days.
東方，木也……執規而治春。其神為歲星，其獸蒼龍，其音角，其日甲乙。
Direction: East · Season: Spring · Planet: Jupiter (歲星) · Animal: Azure Dragon (蒼龍) · Note: jue (角)
Ten Gods for a Yi Wood Day Master
What each of the ten stems is called, seen from this Day Master.
| Stem | Element | Ten God | Chinese |
|---|---|---|---|
| 甲 Jia | Yang Wood | Rob Wealth | 劫财 Jie Cai |
| 乙 Yi | Yin Wood | Friend | 比肩 Bi Jian |
| 丙 Bing | Yang Fire | Hurting Officer | 伤官 Shang Guan |
| 丁 Ding | Yin Fire | Eating God | 食神 Shi Shen |
| 戊 Wu | Yang Earth | Direct Wealth | 正财 Zheng Cai |
| 己 Ji | Yin Earth | Indirect Wealth | 偏财 Pian Cai |
| 庚 Geng | Yang Metal | Direct Officer | 正官 Zheng Guan |
| 辛 Xin | Yin Metal | Seven Killings | 七杀 Qi Sha |
| 壬 Ren | Yang Water | Direct Resource | 正印 Zheng Yin |
| 癸 Gui | Yin Water | Indirect Resource | 偏印 Pian Yin |
Twelve stages of Yi (长生十二宫)
A yin stem runs backward through the branches from its Growth stage.
| Branch | Animal | Stage |
|---|---|---|
| 午 Wu | Horse | 长生 Growth |
| 巳 Si | Snake | 沐浴 Bath |
| 辰 Chen | Dragon | 冠带 Cap and Belt |
| 卯 Mao | Rabbit | 临官 Taking Office |
| 寅 Yin | Tiger | 帝旺 Prosperity |
| 丑 Chou | Ox | 衰 Decline |
| 子 Zi | Rat | 病 Sickness |
| 亥 Hai | Pig | 死 Death |
| 戌 Xu | Dog | 墓 Tomb |
| 酉 You | Rooster | 绝 Extinction |
| 申 Shen | Monkey | 胎 Conception |
| 未 Wei | Goat | 养 Nurture |
The six Yi day pillars
Yi pairs only with the yin branches, so it appears in six of the sixty pillars.
Next Yi days
China Standard Time dates; one day in every ten.
- Oct 28, 2026 · 乙亥
- Nov 7, 2026 · 乙酉
- Nov 17, 2026 · 乙未
- Nov 27, 2026 · 乙巳
- Dec 7, 2026 · 乙卯
- Dec 17, 2026 · 乙丑
FAQ
How do I find out if my Day Master is Yi Wood?
Your Day Master is the stem of your day pillar. Enter your birth date, time and time zone in the BaZi calculator; if the day pillar starts with 乙, your Day Master is Yi.
What is a Yi Wood Day Master?
A BaZi chart whose day pillar has 乙 (Yi) as its stem. Yi is the second of the ten Heavenly Stems, the yin stem of wood. The Di Tian Sui annotation describes it as the wood of branches and leaves (乙為枝葉之木).
What is the difference between Yi and Jia?
Both are wood. Yi (乙) is the yin stem and Jia (甲) the yang one. The Di Tian Sui annotation describes Yi as the wood of branches and leaves and Jia as the wood of root and trunk. Yi combines with Geng and Jia with Ji.
Which stem combines with Yi, and which clashes with it?
Yi combines with 庚 Geng (the 乙庚 combination, associated with Metal). It clashes with 辛 Xin.
How common is a Yi Day Master?
The day stems repeat every ten days without a break, so exactly one day in ten is a Yi day. The next ones are Oct 28, 2026, Nov 7, 2026, Nov 17, 2026 (China Standard Time dates).
Where does Yi sit in the twelve stages?
In the usual twelve-stage table, Yi has its Chang Sheng (Growth) in 午 Wu and its Di Wang (Prosperity) in 寅 Yin; as a yin stem it moves backward through the branches.
Other Day Masters
Sources: 滴天髓 (Di Tian Sui), 天干論, on Chinese Wikisource; 淮南子 (Huainanzi), 天文訓, on Chinese Wikisource; Ten God names as in 淵海子平 (Yuan Hai Zi Ping) on Chinese Wikisource. This page describes the traditional system and quotes classical texts; it is not a character reading, a prediction or advice. Terms are given in simplified characters; quotations keep the script of their source. Day pillars: how they are calculated and checked.