A birth year carrying a 己 (Jǐ) heavenly stem fixes the stems of all twelve months in advance. This is the bazi month stem table for ji year charts, produced by the Five Tigers rule (五虎遁 wǔhǔdùn): a 己 year opens its first month on 丙 (Bǐng), then each month steps forward one stem. The complete year follows.
The 12 month pillars for a Ji 己 year
Months turn at a major solar term (節 jié), not on a calendar date. Find your birth branch and read across to the pillar.
| 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 |
A 己 year opens on 丙 fire and reaches its own stem 己 in the fourth month, the Snake. The pattern is identical to a 甲 year, which is no accident — the two share a column under the Five Tigers rule.
Which years are 己 years
Calendar years ending in 9 carry the 己 stem: 1989, 1999, 2009, 2019. As always the Ba Zi year opens at Li Chun (立春 lìchūn), and 2009 makes the point sharply: Li Chun 2009 fell on 4 February at 00:49, so a birth on 3 February 2009 — the day before — still belonged to the 2008 戊 year and reads from the Wu-year column. Every January birth of a calendar 己 year likewise stays on the previous table. Only from the Li Chun moment onward does this page apply.
A worked example
Take a birth in the Monkey month (申 Shēn) of a 己 year. The seventh row gives 壬申 (Rén Shēn) — a 壬 water stem over a 申 metal branch, water sitting on the metal that generates it, a clean autumn pillar. The Monkey month opens at Li Qiu (立秋 lìqiū) around 7 August, so a birth on 5 August of that year is still in the Goat month and reads 辛未 (Xīn Wèi) instead. The difference is a few days on the calendar and a completely different month pillar, which is why the solar term must be checked first. For what each of those branches then contributes — the Monkey’s rising Metal and hidden Water, the Goat’s hot stored Wood — see the Monkey month page and the Goat month page.
What the month pillar governs
The month pillar holds the month palace, read first for career climate and for parents and elders. Its structural weight is larger still, because the month branch carries the season’s ruling element and the season sets the chart’s baseline temperature. This is why the month branch is decisive when we judge a strong or weak Day Master — a Day Master in its own season begins with real support. In a 己 year the month stems lean on fire and earth early and metal and water later, shaping how the season’s help reaches the Day Master.
Behind that judgement stands the season gate: the branches divide into spring 寅卯辰, summer 巳午未, autumn 申酉戌 and winter 亥子丑, and each season assigns the Day Master one of the five states (旺相休囚死 wàng xiàng xiū qiú sǐ), from Prosperous at the top to Dormant at the bottom. In the 壬申 example above, a Ji Earth Day Master enters autumn at the Resting grade — Earth quietly draining into the season’s Metal — a position read fully in Ji Earth born in autumn.
Reading it in context
Take the month stem as a first move, not a verdict; it works with the branch’s hidden stems and the rest of the chart. Under the Five Tigers rule, 己 and 甲 (Jiǎ) years share this column, so the month table for Jia 甲 years matches this one line for line. The master month stem table shows all five columns, and the hour stem table applies the same logic to the hour of birth.
Ji-year month stem FAQ
How does the formula give 丙 as the opening stem?
The rule reads: 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. Numbering 甲 as 0, 己 is 5, and 5 mod 5 = 0, so the result is 2 — the stem 丙 — exactly as a 甲 year gets. That shared remainder is the whole reason the two stems use one table.
Which row is the 己 year’s own signature?
The fourth month, 己巳 — the year stem repeating on the Snake month. If you spot 己巳 in a chart’s month column, the year stem was either 己 or its column partner 甲, and for 甲 the Snake month reads 己巳 as well, so the signature confirms the column rather than the year.
Was my January 2009 birth a 己 chart?
No. January 2009 precedes Li Chun 2009 (4 February, 00:49), so the year pillar is still 2008’s 戊子 and the month pillar comes from the Wu-year column — its 乙丑 Ox month for most of January.
Confirm your own Ji-year month pillar against the exact solar-term boundary — plot your full chart free with the Butcher Boy calculator and read it back against the table above.