--- type: Knowledge Base title: "BaZi (Four Pillars) Knowledge Base (八字四柱知識庫)" description: "An Open Knowledge Format reference for BaZi (Four Pillars of Destiny): the ten Day Masters, the Ten Gods and the five elements." resource: https://localpapa.com/tools/bazi.html tags: [bazi, four-pillars, ba-zi, zi-ping, okf] timestamp: 2026-06-21T00:00:00Z --- # BaZi · Four Pillars Knowledge Base · 八字四柱知識庫 **BaZi** (八字, "Eight Characters" / Four Pillars of Destiny) maps a birth moment to four pillars — **year, month, day and hour** — each a heavenly **stem** over an earthly **branch** (eight characters in all). The **day stem is the Day Master** (the self); the other stems and branches are read through the **Ten Gods** and the **five elements**. This is the **static knowledge layer** in [Open Knowledge Format](https://cloud.google.com/blog/products/data-analytics/how-the-open-knowledge-format-can-improve-data-sharing/): stable, human- and agent-readable. The **dynamic layer** — casting the four pillars — runs 100% in the browser at , with nothing uploaded. ## How the pillars are cast 1. **Year:** the stem-branch of the year, bounded by **Lì Chūn (立春, Sun at 315° ecliptic)** — a birth before Lì Chūn belongs to the previous year. 2. **Month:** the branch is set by the **solar term** (the Sun’s ecliptic longitude); the stem follows the year stem (五虎遁). 3. **Day:** the stem-branch from the continuous 60-jiazi day cycle (anchored astronomically). 4. **Hour:** the branch from the two-hour period; the stem follows the day stem (五鼠遁). > Note: this tool uses **solar-term** month boundaries and treats the late Zi hour as the same civil day. Schools differ on some details; for entertainment and reference. ## Navigate - [The Ten Day Masters](./daymasters/index.md) — 十天干日主 - [The Ten Gods](./tengods/index.md) — 十神 - [Decade Luck & Strength](./luck.md) — 大運與日主強弱（含藏干與計量方法） - [Annual Fortune](./annual.md) — 流年 --- *Part of the [LocalPapa knowledge pack](../index.md). Tool: [BaZi chart](https://localpapa.com/tools/bazi.html).*