The ten stems at a glance
The stems are counted in a fixed order, and the order matters: it generates the sixty-pair cycle together with the twelve branches. Odd-numbered stems are yang and even-numbered stems are yin, and each element takes two neighbouring places.
| # | Stem | Pinyin | Element | Common image |
|---|---|---|---|---|
| 1 | 甲 | Jiǎ | Yang Wood | tall tree |
| 2 | 乙 | Yǐ | Yin Wood | plants, vines |
| 3 | 丙 | Bǐng | Yang Fire | the sun |
| 4 | 丁 | Dīng | Yin Fire | lamp or candle flame |
| 5 | 戊 | Wù | Yang Earth | mountain, dyke |
| 6 | 己 | Jǐ | Yin Earth | field soil |
| 7 | 庚 | Gēng | Yang Metal | raw ore, axe |
| 8 | 辛 | Xīn | Yin Metal | jewellery, fine metal |
| 9 | 壬 | Rén | Yang Water | river, ocean |
| 10 | 癸 | Guǐ | Yin Water | rain, dew |
The images in the last column are a modern teaching shorthand, not a classical definition, but they follow the spirit of the old verses quoted below. San Ming Tong Hui explains the meaning of the word “stem” with a tree metaphor: stems are the strong trunk, branches the weaker boughs.
夫干犹木之干，强而为阳；支犹木之枝，弱而为阴。“A stem is like the trunk of a tree: strong, and so yang. A branch is like the boughs of a tree: weaker, and so yin.”— San Ming Tong Hui 《三命通會》, 卷一 · 论支干源流. Original text: Wikisource · also on ctext.org (different edition). Translation: bazimethod.
It also quotes the Han scholar Cai Yong on the alternative names “ten mothers” and “twelve children”:
干，干也。其名有十，亦曰十母，即今甲乙丙丁戊己庚辛壬癸是也““Stem” means trunk. There are ten of them, also called the ten mothers; they are today’s Jia, Yi, Bing, Ding, Wu, Ji, Geng, Xin, Ren and Gui.”— San Ming Tong Hui 《三命通會》, 卷一 · 论支干源流. Original text: Wikisource · also on ctext.org (different edition). Translation: bazimethod.
Yin and yang stems
The five yang stems are 甲 丙 戊 庚 壬 and the five yin stems are 乙 丁 己 辛 癸. San Ming Tong Hui states the principle simply:
十干五阳五阴，阳者为刚，阴者为柔“Of the ten stems, five are yang and five are yin; the yang are firm and the yin are yielding.”— San Ming Tong Hui 《三命通會》, 卷二 · 论天干阴阳生死. Original text: Wikisource · also on ctext.org (different edition). Translation: bazimethod.
Polarity matters in practice. It decides the difference between pairs of ten gods (for example Direct Officer versus Seven Killings), it decides which way the luck pillars run, and the Di Tian Sui uses it to describe temperament. Its opening chapter singles out 丙 as the most yang stem and 癸 as the most yin:
五陽皆陽丙為最，五陰皆陰癸為至。“All five yang stems are yang, but Bing is the utmost; all five yin stems are yin, but Gui is the extreme.”— Di Tian Sui (Drops from Heaven’s Marrow) 《滴天髓》, 通天論. Original text: Wikisource · also on ctext.org (different edition). Translation: bazimethod.
The Di Tian Sui verses on each stem
The best-known classical description of the stems is the “Heavenly Stems” chapter of the Di Tian Sui: ten short verses, one per stem, each of eight four-character phrases. They are dense and allusive, and Chinese teachers usually explain them line by line. We give the opening phrases and a literal translation; follow the link to read the full verse and its traditional commentary.
甲 Jia — yang wood
甲木參天，脱胎要火，春不容金，秋不容土“Jia wood reaches to the sky; to shed its womb it needs fire. In spring it does not tolerate metal; in autumn it does not tolerate earth.”— 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.
The image is a great tree. The commentary reads “needs fire” as wood’s need to express itself (fire is the child of wood in the generating cycle).
乙 Yi — yin wood
乙木雖柔，刲羊解牛，懷丁抱丙，跨雞乘猴“Yi wood, though soft, can cut through the goat and loosen the ox; holding Ding and embracing Bing, it can ride the rooster and mount the monkey.”— 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 is supple — grass and vines — but resilient: the goat and ox are the earth branches 未 and 丑, the rooster and monkey the metal branches 酉 and 申.
丙 Bing — yang fire
丙火猛烈，欺霜侮雪，能煆庚金，逄辛反怯“Bing fire is fierce; it scorns frost and mocks snow. It can forge Geng metal, yet meeting Xin it turns timid.”— 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.
The last phrase points to the 丙–辛 stem combination discussed below.
丁 Ding — yin fire
丁火柔中，內性昭融，抱乙而考，合壬而忠“Ding fire is gentle and centred, bright and warm within; holding Yi it is filial, combining with Ren it is loyal.”— 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.
戊 Wu — yang earth
戊土固重，既中且正，靜翕動闢，萬物司命“Wu earth is solid and heavy, central and upright; still, it gathers, moving, it opens — it governs the fate of all things.”— 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.
己 Ji — yin earth
己土卑濕，中正蓄藏，不愁木盛，不畏水旺“Ji earth is low and moist, central and upright, storing and holding; it does not worry about abundant wood nor fear strong water.”— 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.
庚 Geng — yang metal
庚金帶煞，剛強為最，得水而清，得火而銳“Geng metal carries a killing edge, the hardest of all; with water it becomes clear, with fire it becomes sharp.”— 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.
辛 Xin — yin metal
辛金軟弱，溫潤而清，畏土之疊，樂水之盈“Xin metal is soft, warm, lustrous and clear; it fears piled-up earth and delights in abundant water.”— 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.
壬 Ren — yang water
壬水汪洋，能洩金氣，剛中之德，周流不滯“Ren water is vast as the ocean and can drain the energy of metal; firm at its centre, it flows everywhere without stagnating.”— 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.
癸 Gui — yin water
癸水至弱，達於天津“Gui water is the weakest, yet it reaches the ford of Heaven.”— 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.
Stem combinations (天干五合)
Each yang stem “combines” with the yin stem five places after it: 甲–己, 乙–庚, 丙–辛, 丁–壬, 戊–癸. San Ming Tong Hui explains combination with a marriage metaphor: two yang stems compete, two yin stems are insufficient, and only yin with yang combines.
夫合者，乃和谐之义，如阳见阳，二阳相竞则为克，阴见阴，二阴不足则为克，唯阴见阳，阳见阴为合，亦如男女相合而成夫妇之道。“Combination means harmony. When yang meets yang, the two compete, and that is control; when yin meets yin, the two are insufficient, and that is also control. Only yin meeting yang, or yang meeting yin, makes a combination — like man and woman joining in marriage.”— San Ming Tong Hui 《三命通會》, 卷二 · 论十干合. Original text: Wikisource · also on ctext.org (different edition). Translation: bazimethod.
The same chapter tells the story behind 乙–庚: wood fears metal, so the elder brother 甲 marries his younger sister 乙 into the metal family as the wife of 庚.
甲兄遂将乙妹嫁金家，与庚为妻，所以乙与庚合。“Elder brother Jia therefore married younger sister Yi into the metal family as Geng’s wife; that is why Yi combines with Geng.”— San Ming Tong Hui 《三命通會》, 卷二 · 论十干合. Original text: Wikisource · also on ctext.org (different edition). Translation: bazimethod.
In chart reading, a combination can bind two stems so that they act less freely, and under strict conditions classical texts say the pair can “transform” into another element. Whether a combination transforms is one of the more debated topics; we cover it on the combinations and clashes page.
Stems and the sixty-pair cycle
Stems never appear alone in a pillar; each sits on a branch. Pairing the ten stems and twelve branches in step — 甲子, 乙丑, 丙寅 and so on — returns to 甲子 after sixty steps, because sixty is the least common multiple of ten and twelve. A yang stem is only ever paired with a yang branch and a yin stem with a yin branch, which is why there are sixty valid pillars rather than 120. The same cycle counts years (2024 was 甲辰, 2025 乙巳, 2026 丙午), months, days and double-hours. Two consequences follow. First, the year stem tells you the last digit of a Gregorian year: years ending in 4 have 甲, ending in 5 have 乙, and so on through 3 for 癸 — but remember the Bazi year starts at 立春 in early February. Second, the month and hour stems are not free: they are fixed by the year and day stems through two well-known rules, described on the solar terms page.
Stems and the seasons
Classical writers almost never judge a stem in isolation. They ask what season it was born in, because the month decides which element is at its peak. A 甲 wood Day Master born in spring is “in season”; the same stem born in autumn, when metal rules, is out of season and is read very differently. That is the logic behind the 甲 verse above (“in spring it does not tolerate metal; in autumn it does not tolerate earth”). We explain the seasonal cycle of prosperity and decline on the five elements page and the twelve growth stages on the life stages page.
A note on the modern “personality” readings
Many websites turn each stem into a personality type — 甲 the leader, 乙 the diplomat, 丙 the performer and so on. Those descriptions are modern extrapolations from images such as “the tree” or “the sun”. They are not in the classical verses, which describe how each stem behaves when it meets other elements and seasons, not what kind of person it produces. When you read stem descriptions, check whether the writer is quoting a source or improvising.
How stems appear in your chart
Your chart shows four visible stems, one atop each pillar, plus the hidden stems inside the branches. The day stem is your Day Master; the others are read as ten gods relative to it. Calculate your chart to see your four stems, their elements and their ten-god labels side by side.
Keep learning
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.