八字入門：四柱、天干地支與五行怎麼看

作者：Wei Chun Chuang・2026-10-15

「八字」是把一個人出生的年、月、日、時，用天干地支記下來的方法。每個時間單位寫成一組干支，共四組、八個字，所以也叫「四柱八字」。這篇帶你認識四柱、天干地支與五行，讀懂一張命盤最基本的結構。

什麼是四柱？

四柱分別是年柱、月柱、日柱、時柱。每一柱由上面的一個天干和下面的一個地支組成。例如某人的日柱是「甲子」，甲是天干，子是地支。

四柱合起來正好八個字，這就是「八字」名稱的由來。

天干和地支各有哪些？

天干有十個：甲、乙、丙、丁、戊、己、庚、辛、壬、癸。

地支有十二個：子、丑、寅、卯、辰、巳、午、未、申、酉、戌、亥。

天干與地支依序配對，從甲子、乙丑一路排下去，排到癸亥正好六十組，稱為「六十甲子」，然後再從甲子重新開始。古人就是用這套循環來記年、月、日、時。

天干地支怎麼對應五行？

五行是木、火、土、金、水。每個天干和地支都歸屬於一種五行，天干還分陰陽：

地支方面，寅卯屬木，巳午屬火，申酉屬金，亥子屬水，辰戌丑未屬土。地支裡面還「藏」有天干，稱為藏干，進階閱讀時會用到。

五行之間有什麼關係？

五行有兩種基本關係。相生：木生火、火生土、土生金、金生水、水生木，像一路傳遞、滋養的循環。相剋：木剋土、土剋水、水剋火、火剋金、金剋木，代表制衡與約束。

生與剋都是中性的描述，不是好壞。一張命盤裡有生有剋，才構成整體的樣貌。

四柱是怎麼排出來的？

年柱一般以立春作為一年的分界，而不是農曆初一；月柱以節氣為分界，例如立春到驚蟄之間是寅月；日柱依六十甲子逐日推算；時柱以兩小時為一個時辰，例如晚上十一點到凌晨一點是子時。

因為牽涉節氣與時區，出生時間和地點都會影響排盤，所以現在多半交給萬年曆或軟體計算。

看一張命盤要從哪裡開始？

  1. 找到「日主」，也就是日柱的天干，它代表命盤中的「自己」。
  2. 把八個字各自標上五行，看看哪些五行多、哪些少。
  3. 觀察其他天干地支和日主是相生還是相剋。

這三步做熟了，就能進一步學十神、合與沖等主題。

常見問題

八字和生肖有什麼關係？
生肖對應年柱的地支，例如子年屬鼠、丑年屬牛。生肖只看年支，八字則看完整的四柱。
為什麼年柱不是從農曆新年開始？
八字的年與月以節氣劃分，一年從立春開始。因此在立春前後出生的人，年柱可能和一般認知的生肖年不同。
八字裡五行分布不平均要緊嗎？
八個字只有八個位置，五行分布不平均很常見。學習時先把它當成命盤結構的描述，再搭配日主與其他關係一起看。

想用 App 練習？

如果想用自己的命盤練習，時來－八字是一款教你讀八字的 iPhone 課程 App：四柱由 App 計算，20 堂白話課從四柱、天干地支與五行講起，前三堂免費，正好涵蓋本文的內容。目前已送 App Store 審核，尚未上架。

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Bazi for beginners: how to read the four pillars, stems, branches and the Five Phases

作者：Wei Chun Chuang・2026-10-15

Bazi, often called the Four Pillars of Destiny, records the year, month, day and hour of a person's birth using heavenly stems and earthly branches. Each unit of time is written as one stem-branch pair, giving four pairs and eight characters; "bazi" literally means "eight characters". This article introduces the four pillars, the stems and branches and the Five Phases, so you can follow the basic structure of a chart.

What are the four pillars?

The four pillars are the year pillar, month pillar, day pillar and hour pillar. Each pillar is one heavenly stem on top and one earthly branch below. For example, if someone's day pillar is Jia-Zi, Jia is the stem and Zi is the branch.

Four pillars of two characters each make eight characters, which is where the name comes from.

What are the heavenly stems and earthly branches?

There are ten heavenly stems: Jia, Yi, Bing, Ding, Wu, Ji, Geng, Xin, Ren, Gui.

There are twelve earthly branches: Zi, Chou, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu, Hai.

Stems and branches are paired in order, Jia-Zi, Yi-Chou and so on, until Gui-Hai completes sixty pairs, the sexagenary cycle, which then starts again from Jia-Zi. This cycle was used to record years, months, days and hours.

How do stems and branches map to the Five Phases?

The Five Phases (also called Five Elements) are Wood, Fire, Earth, Metal and Water. Every stem and branch belongs to one phase, and stems also have a polarity:

  • Jia (yang) and Yi (yin): Wood
  • Bing (yang) and Ding (yin): Fire
  • Wu (yang) and Ji (yin): Earth
  • Geng (yang) and Xin (yin): Metal
  • Ren (yang) and Gui (yin): Water

For branches: Yin and Mao are Wood, Si and Wu are Fire, Shen and You are Metal, Hai and Zi are Water, and Chen, Xu, Chou and Wei are Earth. Branches also contain "hidden stems", which become important in more advanced reading.

How do the Five Phases relate to each other?

There are two basic relationships. Generation: Wood feeds Fire, Fire makes Earth, Earth bears Metal, Metal carries Water, Water nourishes Wood, a cycle of passing on and nurturing. Control: Wood controls Earth, Earth controls Water, Water controls Fire, Fire controls Metal, Metal controls Wood, a cycle of checks and balances.

Both are neutral descriptions, not good or bad. A chart contains both, and together they form its overall shape.

How are the four pillars calculated?

The year pillar usually changes at Lichun, the "Start of Spring" solar term, rather than at Lunar New Year. Month pillars change at solar terms too; for example, the period from Lichun to Jingzhe is the Yin month. The day pillar follows the sixty-day cycle, and the hour pillar uses two-hour periods; for example, 11 p.m. to 1 a.m. is the Zi hour.

Because solar terms and time zones are involved, birth time and place both affect the chart, so most people now let a perpetual calendar or software do the calculation.

Where do you start reading a chart?

  1. Find the Day Master: the heavenly stem of the day pillar, which represents "you" in the chart.
  2. Label each of the eight characters with its phase and see which phases are plentiful and which are scarce.
  3. Notice whether the other stems and branches generate or control the Day Master.

Once these three steps feel familiar, you are ready for topics such as the Ten Gods, combinations and clashes.

常見問題

How does Bazi relate to the Chinese zodiac animal?
Your zodiac animal is the branch of the year pillar, for example Zi is the Rat and Chou is the Ox. The zodiac looks only at the year branch; Bazi looks at all four pillars.
Why doesn't the year pillar start at Lunar New Year?
Bazi divides years and months by solar terms, and the year begins at Lichun. People born near Lichun may therefore have a year pillar that differs from the zodiac year they expect.
Does it matter if the Five Phases are unevenly spread in my chart?
Eight characters can't cover five phases evenly, so an uneven spread is very common. While learning, treat it as a description of the chart's structure and read it together with the Day Master and the other relationships.

Practise with an app

To practise on your own chart, Shilai – Bazi is an iPhone course that teaches you to read Bazi: the app calculates the four pillars, and twenty plain-language lessons start from the pillars, stems, branches and Five Phases. The first three lessons are free and cover the material in this article. It is currently in App Store review.

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