天光

tiān guāng

Light of heaven · tian guang

Also rendered: light of heaven (Literal, and keeps the phrase available in both its senses) · the heavenly light (Slightly more devotional in register than the Chinese is)

Cosmology

Reviewed · 2026-09

At a glance

Pinyin: tiān guāng
Simplified: 天光
Literal: 天 is heaven, and 光 is light — 說文 enters 光 as 明, glossed 从火在人上, a fire above a person's head, which is as good a picture of illumination as any. The compound is not metaphorical in chapter 26. It is the thing the physician is told to match his practice to: after 法天則地 — take heaven as model, earth as standard — the third instruction is 合以天光, join it to the light of the sky. Since the rest of the chapter is about watching the sun, the moon, the stars and the season, 天光 means those lights themselves, read as signals rather than admired.
Shuowen: 《說文解字》：天，顛也。至高無上，从一大；光，明也。从火在人上，光明意也。天光連言，謂天上之日月星辰之光。本篇之目：法天則地，合以天光。

In brief

The light of the sky — sun, moon, stars — as something to be read and matched rather than merely seen. Chapter 26 opens its answer with a three-part rule: take heaven as the model, earth as the standard, and join the two to the light of heaven. The third clause is the operative one, because everything that follows — watching the moon’s phases before you drain or supplement, tracking the shifting light to fix the site, standing square and waiting — is a specification of it. The same phrase appears in chapter 25, where it governs the whole argument of that chapter rather than the calendar.

Senses in the classical corpus

The light to be matched 合以天光

法天則地而後合以日月星辰之光

法天則地，合以天光 — Suwen 26

What the calendar is made of 必𠉀日月星辰四時八正之氣

天光之實，即日月星辰之候

凡剌之法，必𠉀日月星辰四時八正之氣，氣定乃剌之 — Suwen 26

What is tracked to fix the site 移光定位

光影推移即天光之可測者

移光定位，正立而待之 — Suwen 26

Spoken as brightness of mind elsewhere 神明

與第八篇「神明」之目義近而非一物

心者，君主之官，神明出焉 — Suwen 8

The same phrase, wider use 合以天光

第二十五篇亦用此語，總該全篇之旨

法天則地，合以天光 — Suwen 25

Not a metaphor for insight 天光

舊注有以天光為神明之喻者，本篇上下文皆實指日月，不取

天寒日陰，則人血凝泣而衛氣沈 — Suwen 26

Occurrences in the classics

Passages where the term does real work, with the original, pinyin and English on the same line.

Display

2 passages

素問·八正神明論 Suwen 26 · 八正神明論 Read in context →

歧伯對曰：法天則地，合以天光。歧伯对曰：法天则地，合以天光。

Qí bó duì yuē: fǎ tiān zé dì, hé yǐ tiān guāng.

Qibo replies: Model yourself on heaven, take earth as your standard, and join these to the light of the sky.

全篇之綱只此八字：法天、則地、合以天光。「合」讀 hé，是動詞——不是說醫者心中默會天光，而是要拿天時之光象去「合」上用針之時。下文「必𠉀日月星辰四時八正之氣，氣定乃剌之」即是這一句的展開：所候者，正是天光。「移光定位，正立而待之」尤為切近——「移」讀 yí，光影之推移可以測定部位，故天光是可測、可待的實在之物，不是形容醫者心地光明的比喻。舊注有以天光為「神明」之喻者，於本篇上下文為遠，不取。又第二十五篇開卷亦用「合以天光」四字，彼處統攝全篇之旨，此處則專起候時之說，同一語而所指有廣狹之別。

素問·三部九候論 Suwen 20 · 三部九候論 Read in context →

黄帝問曰：余聞九鍼於夫子，衆多博大，不可勝數。余願聞要道，以屬子孫，傳之後世，著之骨髓，藏之肝肺，歃血而受，不敢妄泄，令合天道，必有終始。上應天光，星辰歷紀，下副四時五行。貴賤更互，冬陰夏陽，以人應之，奈何？願聞其方。黄帝问曰：余闻九针于夫子，众多博大，不可胜数。余愿闻要道，以属子孙，传之后世，著之骨髓，藏之肝肺，歃血而受，不敢妄泄，令合天道，必有终始。上应天光，星辰历纪，下副四时五行。贵贱更互，冬阴夏阳，以人应之，奈何？愿闻其方。

Huáng dì wèn yuē: yú wén jiǔ zhēn yú fū zǐ, zhòng duō bó dà, bù kě shèng shǔ. Yú yuàn wén yào dào, yǐ zhǔ zǐ sūn, chuán zhī hòu shì, zhù zhī gǔ suǐ, cáng zhī gān fèi, shà xuè ér shòu, bù gǎn wàng xiè, lìng hé tiān dào, bì yǒu zhōng shǐ. Shàng yìng tiān guāng, xīng chén lì jì, xià fù sì shí wǔ xíng. Guì jiàn gēng hù, dōng yīn xià yáng, yǐ rén yìng zhī, nài hé? Yuàn wén qí fāng.

The Yellow Emperor asks: I have heard the nine needles from you, Master — vast and broad, more than can be counted. What I wish to hear is the essential way, so that I may entrust it to sons and grandsons and hand it on to later generations, inscribe it in bone and marrow, store it in liver and lung, and receive it over smeared blood, never daring to leak it out rashly — let it accord with the way of heaven and have both an ending and a beginning. Above it answers to the light of heaven and to the ordered courses of the stars; below it is paired with the four seasons and the five phases. Noble and base alternate, winter is yin and summer yang — how does the human answer to all this? I wish to hear the method.

「上應天光」——天光星辰曆紀在上，四時五行在下，以人應之；**「天光」本篇1見**

Compounds built on this term

天光

tiān guāng

light of heaven

本篇用針之總綱，法天則地而合之

法天則地

fǎ tiān zé dì

taking heaven as law and earth as rule

本站已立目（id 796），與天光連言

日月星辰

rì yuè xīng chén

sun, moon, stars and constellations

天光之目，本篇四者並列

神明

shén míng

shenming · spirit brightness

本站已立目（id 352），與天光義別

How it has been translated

Every rendering below is a decision about which reader is being addressed. There is no neutral option.

Wiseman & Feng	heaven's light	They keep 天 as heaven throughout, which preserves the technical pairing with 地 rather than drifting toward 'sky' or 'nature'.
Unschuld	the light of heaven	Unschuld's rendering is identical in substance; he notes in his commentary that the phrase is to be understood concretely as sun, moon and stars.
This site	light of heaven	We keep the literal reading because this chapter spends its first half specifying exactly which lights are meant and what each of them does to the blood. 'Sky' would lose the 天/地 pairing that the sentence sets up in its first four words.

Entry status

Review pending — who reviews this?

2026-09

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