If your birth year carries a 甲 (Jiǎ) heavenly stem, the stems of all twelve months are already decided. This is the bazi month stem table for jia year charts, derived from the Five Tigers rule (五虎遁 wǔhǔdùn): a 甲 year opens its first month on 丙 (Bǐng), and every month after that steps forward one stem. What follows is the full run, month by month, so you can read your month pillar straight off the row.
The 12 month pillars for a Jia 甲 year
Each month begins at a major solar term (節 jié), not on a calendar date. Find the branch you were born under and read across.
| Month | Branch | Starts at (solar term) | Month pillar |
|---|---|---|---|
| 1st | Tiger 寅 Yín | Li Chun 立春 (~4 Feb) | 丙寅 Bǐng Yín |
| 2nd | Rabbit 卯 Mǎo | Jing Zhe 惊蛰 (~6 Mar) | 丁卯 Dīng Mǎo |
| 3rd | Dragon 辰 Chén | Qing Ming 清明 (~5 Apr) | 戊辰 Wù Chén |
| 4th | Snake 巳 Sì | Li Xia 立夏 (~5 May) | 己巳 Jǐ Sì |
| 5th | Horse 午 Wǔ | Mang Zhong 芒种 (~6 Jun) | 庚午 Gēng Wǔ |
| 6th | Goat 未 Wèi | Xiao Shu 小暑 (~7 Jul) | 辛未 Xīn Wèi |
| 7th | Monkey 申 Shēn | Li Qiu 立秋 (~7 Aug) | 壬申 Rén Shēn |
| 8th | Rooster 酉 Yǒu | Bai Lu 白露 (~7 Sep) | 癸酉 Guǐ Yǒu |
| 9th | Dog 戌 Xū | Han Lu 寒露 (~8 Oct) | 甲戌 Jiǎ Xū |
| 10th | Pig 亥 Hài | Li Dong 立冬 (~7 Nov) | 乙亥 Yǐ Hài |
| 11th | Rat 子 Zǐ | Da Xue 大雪 (~7 Dec) | 丙子 Bǐng Zǐ |
| 12th | Ox 丑 Chǒu | Xiao Han 小寒 (~5 Jan) | 丁丑 Dīng Chǒu |
Notice that a 甲 year begins and ends on 丙 and 丁, the two fire stems, and reaches its own stem 甲 in the ninth month, the Dog. That pattern is the signature of the Jiǎ column.
How the Five Tigers rule produces this column
The rule is compact enough to state in one line: first-month (寅) stem index = (year-stem-index mod 5) × 2 + 2; each later month adds 1, mod 10. Year stems pair: 甲/己, 乙/庚, 丙/辛, 丁/壬, 戊/癸 share columns. Number the stems 甲 0, 乙 1, 丙 2, 丁 3, 戊 4, 己 5, 庚 6, 辛 7, 壬 8, 癸 9. For a 甲 year the index is 0, so (0 mod 5) × 2 + 2 = 2, which is 丙 — the Tiger month opens on 丙寅, and the remaining eleven months simply count forward one stem each. Every row in the table above is that single formula unrolled.
Which years use the Jia table
Calendar years ending in 4 carry the 甲 stem — 1984, 1994, 2004, 2014 and 2024 among them — with one standing caveat: the Ba Zi year begins at Li Chun (立春 lìchūn), around 4 February, not on 1 January and not at Chinese New Year. A birth in January of a calendar 甲 year therefore still belongs to the previous 癸 year and must use that column instead. The reverse also holds: a birth in January 1985 sits inside the 甲 year that began at Li Chun 1984, so this table applies to it.
A worked example
Take someone born in the Horse month (午 Wǔ) of a 甲 year. Run down to the fifth row and the pillar is 庚午 (Gēng Wǔ) — a 庚 metal stem sitting on a 午 fire branch. The branch was fixed by the season, since the Horse month opens at Mang Zhong (芒种 mángzhòng) around 6 June; the stem 庚 was fixed the moment we knew the year was 甲. You can read that month’s full seasonal behaviour in the Horse month profile. If that same person were born a few days before Mang Zhong, they would still belong to the Snake month, and the pillar would read 己巳 (Jǐ Sì) instead. The boundary is the whole game, which is why the solar term, not the date, decides the row.
What the month pillar governs
The month pillar is the seat of the month palace, and in a working reading it speaks first to career climate and to your relationship with parents and elders. More structurally, the month branch carries the season’s dominant element, and that season sets the baseline temperature of the whole chart. Whether a Day Master reads strong or weak is decided more by the month branch than by any other single character, because being born in your own season is like standing on home ground. For a 甲 year the month stems lean heavily on fire and earth, which colours how the season’s support actually reaches your Day Master.
The branches themselves group into four solar-term seasons — spring 寅卯辰, summer 巳午未, autumn 申酉戌, winter 亥子丑 — and each season grades every Day Master through the five states (旺相休囚死 wàng xiàng xiū qiú sǐ), from Prosperous down to Dormant. A Jia Wood person born in this year’s own ninth month, the 甲戌 Dog month, lands in autumn, Wood’s hardest season; the mechanics of that judgement are worked through in Jia Wood born in autumn and in the Dog month page.
Reading it in context
The month stem never travels alone. It pairs with the branch’s hidden stems and answers to the year and the day, so treat this table as the first step, not the verdict. Because 甲 and 己 (Jǐ) years share the same column under the Five Tigers rule, the month table for Ji 己 years is identical to this one — a useful cross-check. For the master grid of all five columns, see the complete month stem table, and for the parallel logic on the hour, the hour stem table.
Jia-year month stem FAQ
Why do 甲 and 己 years share one table?
Because the formula only uses the year-stem index mod 5, and 甲 (0) and 己 (5) reduce to the same value. The five pairs are fixed: 甲/己, 乙/庚, 丙/辛, 丁/壬, 戊/癸.
I was born in January 1984. Do I use this table?
No. Li Chun 1984 had not yet arrived, so January 1984 still belongs to the previous 癸 year and uses the Gui-year column. Only births from Li Chun 1984 onward take the 甲 table.
Do the solar-term dates in the table move?
Slightly. The dates shown are typical values; the exact moment of each term shifts by hours or a day from year to year, and our convention takes the change at the precise solar-term moment. Near a boundary, only the exact time settles the row.
Confirm your own Jia-year month pillar without misjudging the solar-term boundary — plot your full chart free with the Butcher Boy calculator and match it against the row above.