Code does the chart. AI does the reading.

Chinese astrology (Zi Wei Dou Shu) chart engine

Zi Wei Dou Shu — Chinese "Purple Star" astrology — charts a life from a birth date and hour. A Rust core casts it, with bindings for Rust, Python and Go; every field carries a translated name plus a stable key, and one call turns the whole chart into text an LLM can read. Charts match JS iztro field for field — 716,314 golden cases hold that line.

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天机
兄弟辛巳
紫微
命宫壬午
—
父母癸未
破军
福德甲申
七杀
夫妻庚辰
—
田宅乙酉
太阳禄天梁
子女己卯
廉贞天府
官禄身丙戌
武曲权天相
财帛戊寅
天同忌巨门
疾厄己丑
贪狼
迁移戊子
太阴科
仆役丁亥
Zi Wei Dou Shu
Solar
2000-8-16
Soul
Po Jun
Element
Wood 3
Real output: female, 2000-8-16, Tiger hour — matching the golden dataset field for field
golden cases
716,314
tolerated deviations
0
pattern rules
64
output languages
6

What the model gets

One call renders the whole chart as structured text — paste it into any LLM and start asking. Brackets are brightness and the four transformations; there is a matching call for horoscopes.

How it is generated →
=== Basic Info ===
Gender: female
Solar Date: 2000-8-16
Lunar Date: 二〇〇〇年七月十七
Chinese Date: geng chen - jia shen - bing woo - geng yin
…
Soul Palace Branch: woo
Body Palace Branch: xu
Soul Star: rebel
Body Star: scholar
Five Elements Class: wood 3rd
Birth-Year Mutagen: sunA, generalB, moonC, fortunateD

=== Palaces ===

--- wealth ---
…
Major Stars: general([+1])[B], minister([+3])
Minor Stars: horse
Adjective Stars: considery, senior, ageless, psychic, gourmet, gloomy, upset
… (the other eleven palaces)

x-iztro and iztro

Identical to JS iztro

  • Charts, twelve palaces (body and Original palace included), six horoscope levels
  • Palace queries, surrounded palaces, flying stars
  • Serialized JSON, key for key
  • 716,314 golden cases, zero tolerated deviations

Beyond iztro

  • 64 pattern rules — each hit names its palace, variant and the stars that triggered it
  • Knowledge packs — reading texts in swappable JSON, default pack included
  • Reverse lookup — BaZi pillars or chart features back to birth dates
Full comparison with iztro →
from x_iztro import Astro

astro = Astro()
# time_index 2 = Tiger hour
chart = astro.by_solar("2000-8-16", 2, "female")

chart.soul                # soul star
chart.palace("soulPalace")  # soul palace
chart.patterns()          # pattern hits
astro.astrolabe_to_prompt(chart)  # chart -> text

  • Complete charts and horoscopes

    Natal chart plus six horoscope levels — decadal (a childhood scope runs before it begins), age fortune, yearly, monthly, daily and hourly — with mutagens, flowing stars and surrounded palaces.

  • Configurable schools and boundaries

    Six switches for the year, horoscope, age and late-Rat-hour boundaries, the school and the chart perspective. Defaults match iztro exactly; custom mutagen and brightness tables are supported.

  • Language-independent keys

    Every translatable field carries a stable key. Write the logic once; it behaves identically across all six output languages.

  • An interface built for AI

    Prompt output is deterministic, with a stable field order — usable directly as a tool-call result. The docs ship llms.txt, and every docs page serves plain text with .md appended.

  • No global state
  • Invalid input errors, never panics
  • Python: abi3, zero deps
  • Go: no cgo
  • MIT licensed