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Zi Wei Dou Shu (Purple Star Astrology) · Major star 8 of 14

Tai Yin 太陰, the Moon as a symbol on the board

Tai Yin 太陰 is the Moon as a star of the chart, one palace ahead of Tian Fu. The 紫微斗數全書 calls it the essence of water and the Sun's mate, reads it as waxing and waning round the board, and makes it the mother's star; no real Moon is computed.

The twelve palaces of the board, 巳 午 未 申 along the top, 辰 and 卯 down the left, 酉 and 戌 down the right and 寅 丑 子 亥 along the bottom, each marked with Tai Yin's brightness there by the 全書's seven-level table: brilliant (廟) in 子, 丑, 亥; weak or fallen in 卯, 辰, 巳, 午, 未. The brilliant palaces are outlined, and 太陰 is written in the centre. 子 廟 brilliant 丑 廟 brilliant 寅 旺 strong 卯 陷 fallen 辰 陷 fallen 巳 陷 fallen 午 不 weak 未 不 weak 申 利 beneficial 酉 旺 strong 戌 旺 strong 亥 廟 brilliant 太陰
Tai Yin's brightness in each of the twelve palaces, by the 全書's seven-level table: the brilliant palaces outlined, the weak and fallen ones dashed. 寅 sits at the bottom left, as charts draw the board.

Facts

Order
8 of 14, in the order of the placing verse (安南北斗諸星訣)
Characters
太陰 Tàiyīn; simplified 太阴
On our chart
Moon; in detail, Tai Yin · Moon
Series and place
Tian Fu series (天府星系); one palace ahead of Tian Fu
Element (全書)
Water (水)
Dipper seat (全書)
The essence of water (水之精), the Moon as a star of the middle sky; listed under both Dippers
Epithet (化氣)
富 (fù), abundance
Palace it masters (全書)
Property (田宅); the juan 2 list adds the 財帛 palace
Brilliant (廟) in
子、丑、亥
Weak (不) or fallen (陷) in
卯、辰、巳、午、未
Transformations (common table)
化祿 in 丁 years; 化權 in 戊 years; 化科 in 庚 years; 化科 in 癸 years; 化忌 in 乙 years
Our gloss
Sensitivity, nurture and inner life; quiet, steady building over time (EsoTerrier's wording)

Meaning

The 全書's dialogue begins:

太陰乃水之精,為田宅主,[…]與日為配。

In our translation: Tai Yin is the essence of water, master of the Property palace, [...] the Sun's mate. The quotation leaves out the epithet the line gives it, 化富; the facts give it as 富, abundance.

The text reads the Moon as the Sun reads the day, by the board: it has a waxing and a waning half, and is fallen from 卯 to 未 and at home from 酉 to 丑. A bright Moon, the dialogue says, gives a person who is 「聰明俊秀」, clever and handsome, 「端雅純祥」, upright, graceful and gentle. It fears Ju Men, the Ram and Spinning Top. By the text's own family table it is the mother's star for everyone and the wife's in a man's chart.

The 形性賦 gives it only an image, 「玉兔清奇」, the jade hare, fine and rare: the hare is the animal of the moon.

Our chart calls it the Moon, and our gloss reads: sensitivity, nurture and inner life; quiet, steady building over time.

A symbol, not the Moon

Tai Yin is placed one palace ahead of Tian Fu by counting; no lunar position or phase is computed, and the Moon of a Western natal chart is a different thing that our pages never link to it.

On the board

The Moon shares a palace with Tian Tong in 子 or 午, the Sun in 丑 or 未 and Tian Ji in 寅 or 申, and stands alone in the other six. It is brilliant (廟) in 子, 丑 and 亥, strong in 寅, 酉 and 戌, fallen (陷) in 卯, 辰 and 巳 and weak (不) in 午 and 未. In the common table it takes 化祿 in a 丁 year, 化權 in a 戊 year, 化科 in 庚 and 癸 years and 化忌 in a 乙 year.

What this page leaves out

The 全書 also says what a dim Moon means for a mother, a wife and the eyes. We record that it does and repeat none of it.

Correspondences

Each item with how it stands: “sourced” is in the work cited, “our construction” is EsoTerrier’s own, and “disputed” means the sources disagree.

諸星問答論, the opening line
「太陰乃水之精,為田宅主,[…]與日為配。」 Tai Yin is the essence of water, master of the Property palace, [...] the Sun's mate (with the epithet left out of the quotation; it is given in the facts) sourced
形性賦, form and nature
「玉兔清奇」 the jade hare, fine and rare (the hare is the animal of the moon); a sketch of a type, never a reading of anyone's body sourced
The name in the sky
The Moon in name only: the star is placed one palace from Tian Fu, and no lunar position or phase is computed sourced
Dipper by series
Listed as a Southern Dipper star on some practitioner pages because it belongs to the Tian Fu series; the 全書 calls it a star of the middle sky disputed
化科 in a 庚 year, other tables
The Zhongzhou, 河洛 and 占驗 tables do not give the Moon 化科 in a 庚 year (天府 or 天同 take it instead) disputed
English names elsewhere
Moon Star (English Wikipedia); moon (iztro); the Moon on every site we checked sourced
Our short name and gloss
Moon: Sensitivity, nurture and inner life; quiet, steady building over time. our construction

How the schools read it

紫微斗數全書, 諸星問答論
The essence of water and the Sun's mate, with a waxing and a waning half; it gives a person who is 「聰明俊秀」, clever and handsome, of an upright, graceful and gentle disposition.
紫微斗數全書, the lines under 希夷先生
Fallen from 卯 to 未 and at home from 酉 to 丑; the mother's star for everyone and the wife's in a man's chart, by the text's own reckoning.
紫微斗數全書, 形性賦
"The jade hare, fine and rare": an image of the moon, given as the star's form.
Zhongzhou, 河洛 and 占驗 tables
Do not give the Moon 化科 in a 庚 year; Tian Fu or Tian Tong takes it instead.
Three-harmony practice (三合派)
With the Sun, the star whose brightness teachers weigh most.
EsoTerrier
Short name Moon; our gloss names sensitivity, nurture and inner life, "quiet, steady building over time". Never linked to the Moon of a natal chart, and no reading of outcome.

Claims about it

  • Tai Yin is the Moon of the sky, and the chart computes its position or phase.

    false

    What the record shows: It is placed one palace from Tian Fu by counting; no ephemeris is used. The waxing and waning in the text are a reading of the board, not of the sky.

  • As a star of the Tian Fu series, the Moon belongs to the Southern Dipper.

    false

    What the record shows: The series is a placement grouping. The 全書 puts the Moon in the middle sky.

  • The text's lines on the Moon foretell what befalls a mother or a wife, or harm to the eyes.

    unverified

    What the record shows: The 全書 has such lines. We keep its image of the moon and its pairing with the Sun.

Elsewhere on EsoTerrier

Sources

Primary texts (1)
  1. 紫微斗數全書, juan 1 to 3, attributed to Chen Tuan; a Ming manual, the text labelled Qing on Wikisource, which names no source edition. Chinese Wikisource transcription; our translations. zh.wikisource.org/wiki/紫微斗數全書
Studies and other sources (4)
  1. SylarLong and contributors, iztro 2.6.1, an open-source Zi Wei Dou Shu library (MIT licence), our test oracle; nothing of it ships. github.com/SylarLong/iztro
  2. "Zi Wei Dou Shu", English Wikipedia (orientation and the English names). en.wikipedia.org/wiki/Zi_Wei_Dou_Shu
  3. senjutsu.jp, tables of the four transformations by school, and the calendar disputes (facts only). senjutsu.jp/labo/shibitosuu/shika-taishou
  4. A practitioner's table of the five-phase and yin-yang attributes of the major stars, 2018 (facts only). hansyuan0715.pixnet.net/blog/posts/17238043287
Our own research (2)
  1. EsoTerrier, Zi Wei Dou Shu research: the calculation, the schools, the conventions and the naming, 9 to 13 October 2026.
  2. EsoTerrier calculation engine, the Zi Wei Dou Shu service and its documentation.

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By EsoTerrier. Written with AI assistance from our research and checked against its sources; last revised 19 October 2026. How we write these pages.

First published ; last revised . Corrections: support@esoterrier.com.

Chinese quotations are from public-domain texts as transcribed on Chinese Wikisource (CC BY-SA 4.0); the translations and readings are EsoTerrier's own.