When the birth year carries a 丁 (Dīng) heavenly stem, the stems of all twelve months are already determined. This is the bazi month stem table for ding year charts, drawn from the Five Tigers rule (五虎遁 wǔhǔdùn): a 丁 year opens its first month on 壬 (Rén), then each month steps forward one stem. Here is the whole year in order.
The 12 month pillars for a Ding 丁 year
Months change 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) | 壬寅 Rén Yín |
| 2nd | Rabbit 卯 Mǎo | Jing Zhe 惊蛰 (~6 Mar) | 癸卯 Guǐ Mǎo |
| 3rd | Dragon 辰 Chén | Qing Ming 清明 (~5 Apr) | 甲辰 Jiǎ Chén |
| 4th | Snake 巳 Sì | Li Xia 立夏 (~5 May) | 乙巳 Yǐ Sì |
| 5th | Horse 午 Wǔ | Mang Zhong 芒种 (~6 Jun) | 丙午 Bǐng Wǔ |
| 6th | Goat 未 Wèi | Xiao Shu 小暑 (~7 Jul) | 丁未 Dīng Wèi |
| 7th | Monkey 申 Shēn | Li Qiu 立秋 (~7 Aug) | 戊申 Wù Shēn |
| 8th | Rooster 酉 Yǒu | Bai Lu 白露 (~7 Sep) | 己酉 Jǐ Yǒu |
| 9th | Dog 戌 Xū | Han Lu 寒露 (~8 Oct) | 庚戌 Gēng Xū |
| 10th | Pig 亥 Hài | Li Dong 立冬 (~7 Nov) | 辛亥 Xīn Hài |
| 11th | Rat 子 Zǐ | Da Xue 大雪 (~7 Dec) | 壬子 Rén Zǐ |
| 12th | Ox 丑 Chǒu | Xiao Han 小寒 (~5 Jan) | 癸丑 Guǐ Chǒu |
A 丁 year opens on 壬 water and reaches its own stem 丁 in the sixth month, the Goat. That 丁未, fire meeting late-summer earth, is the signature of the Dīng column.
A worked example
This is one of the most searched cases: a birth in the Pig month (亥 Hài) of a 丁 year. The tenth row gives 辛亥 (Xīn Hài) — a 辛 metal stem on a 亥 water branch, refined metal over early-winter water. The Pig month opens at Li Dong (立冬 lìdōng) around 7 November, so a birth on 5 November of that year is still in the Dog month and reads 庚戌 (Gēng Xū) instead. The pillar hinges entirely on which side of Li Dong the birth falls. Confirm the exact solar-term moment before you settle on 辛亥. The Pig month page then shows what that branch’s strong Water and hidden Wood do to each Day Master.
Which years carry the 丁 stem
Calendar years ending in 7 are 丁 years: 1987, 1997, 2007, 2017. The boundary caveat is worth a concrete case. Li Chun 2017 fell on 3 February at 23:34 — a day earlier than usual — so a child born late on 3 February 2017 was already inside the 丁 year and reads from this table, while a birth two hours earlier still belonged to the previous 丙 year and its Bing-year column. January births of a calendar 丁 year always use the previous column; the year has simply not turned yet.
The mechanics under the table
The Five Tigers rule states: 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. Counting 甲 as 0, a 丁 year has index 3, so (3 mod 5) × 2 + 2 = 8 — stem 8 is 壬, which is why the Tiger month opens on 壬寅. Each of the remaining rows is one stem further along the cycle of ten.
What the month pillar governs
The month pillar houses the month palace, which a practitioner reads for career climate and for the parents and elders around you. It also carries more structural weight than any other pillar for one reason: the month branch holds the ruling element of the season, and the season is the loudest voice on the chart’s overall temperature. That is precisely why the month branch dominates when we judge a strong or weak Day Master — being born in a season that feeds your element is like starting on home ground. In a 丁 year the month stems open on water and pass through fire and earth, shaping how the season’s support actually reaches the Day Master.
The season gate works through the branch groups — spring 寅卯辰, summer 巳午未, autumn 申酉戌, winter 亥子丑 — each grading the Day Master by the five states (旺相休囚死 wàng xiàng xiū qiú sǐ). Take the searched 辛亥 case above: a Ding Fire Day Master born in that Pig month enters winter at the Dormant grade, the hardest seasonal seat Fire receives, examined properly in Ding Fire born in winter. The same table, different month, gives the same person the Prosperous grade in the 丙午 Horse month — read the contrast in the Goat month page, where the year’s own 丁未 signature falls.
Reading it in context
Treat the month stem as an opening, not a verdict; it interacts with the branch’s hidden stems and the rest of the chart. Under the Five Tigers rule, 丁 and 壬 (Rén) years share this column, so the month table for Ren 壬 years matches this one exactly and serves as a check. The master month stem table gathers all five columns, and the hour stem table extends the same logic to the hour pillar.
Ding-year month stem FAQ
Why does a Fire year open on a Water stem?
Because the first month’s stem is computed from the year stem’s index, not borrowed from its element. The formula sends 丁 to 壬, and the pairing 丁/壬 — the very stems that share this column — is a by-product of the same arithmetic.
I was born in January 1997. Which table do I use?
The previous year’s. January 1997 sits before Li Chun 1997, so the Ba Zi year is still 丙 and the month pillar comes from the Bing-year column, most likely its final 辛丑 Ox month row.
Does the month stem change my Day Master?
Never — the Day Master is the day stem, fixed by the day of birth. The month stem adds one character to the elemental count and titles the month palace, but it does not redefine who is standing at the centre of the chart.
Confirm your own Ding-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.