BAZI KNOWLEDGE BASE
How to calculate the Year Pillar: boundary first, sexagenary cycle second
A Year Pillar (the two-symbol column for the birth year) needs two steps: establish which stem-branch year applies under the chosen boundary, then locate its stem and branch in the sixty-pair cycle. The Gregorian year number or animal sign alone can miss the Li Chun (the Start of Spring calendar marker used as the year boundary in many BaZi methods) distinction and the different stems paired with the same animal.
Step one: has that year’s Li Chun occurred?
Under this knowledge base’s Li Chun boundary, the preceding stem-branch year applies until the crossing, after which the new interval begins. This effective year is a calculation label; it does not rewrite the civil birth year. On the transition date, the time matters as well.
Step two: advance the stem and branch together
Using the Observatory’s Gui Mao label for 2023 as a reference, one step forward gives Jia Chen for 2024, then Yi Si for 2025 and Bing Wu for 2026. For BaZi here, each row’s interval starts at that year’s Li Chun, not on 1 January.
| Effective year | Year pair | Animal: branch only |
|---|---|---|
| 2023 | Gui Mao | Rabbit |
| 2024 | Jia Chen | Dragon |
| 2025 | Yi Si | Snake |
| 2026 | Bing Wu | Horse |
A transparent cycle index for calculation
Index Jia Zi as 0, making Gui Mao 39. For effective year Y from step one, calculate 39+(Y−2023), then take a remainder in the range 0–59. Its remainders modulo 10 and 12 identify the stem and branch, both ordered from Jia and Zi at index 0.
For Y=2026, index 42 gives stem remainder 2, Bing, and branch remainder 6, Wu: Bing Wu. Y=2022 gives index 38, Ren Yin. Do not mix traditional one-based numbering with zero-based calculation; a sixty-year interval returns the same pair.
The month stem uses the same established year stem
The Year Stem (the upper symbol in the birth-year column) supplies the Five Tigers starting rule for month stems. After Li Chun 2026, Bing year begins with Geng Yin month; before it, Yi Si year remains in Ji Chou month. Changing the displayed year without updating the deriving stem can leave inconsistent results.
The Year Pillar is only one of four. People with the Horse animal may have different Year Stems and different month, day and hour pillars. A year pair helps explain the chart’s notation; it cannot summarize an individual life.