The mechanism in the hollow · kong zhong zhi ji

Also rendered: The mechanism in the hollow (literal, and it keeps the trigger) · The qi in the point (plain, and it loses the machine)

Physiology

Reviewed · 2026-10-24

At a glance

Pinyin: kōng zhōng zhī jī
Simplified: 空中之机
Literal: 空 kōng — hollow; 中 zhōng — within; 機 jī — the trigger of a crossbow, hence the spring of movement. The hollow is the point; the mechanism is the qi moving in it.
Shuowen: 《說文》：空，竅也；機，主發謂之機，本弩牙之名。「空中」本篇2見，「空中之機」1見；「機」字3見：守機、機之動、空中之機，三處相承。

In brief

The hollow of the point and the movement of qi within it. 機之動不離其空中者，知氣之虚實，用鍼之徐疾也 — the mechanism never leaves its hollow: what moves there tells you whether the qi is excess or deficient, and that decides whether the needle goes slowly or quickly. Then the finer state: 空中之機清浄以微者，鍼以得氣，密意守氣勿失也 — when the mechanism in the hollow is clear and still and subtle, the needle has obtained qi, and the practitioner keeps his mind on it and does not let it go. The word 機 is chosen: a trigger is not a substance but the point at which something is released.

Senses in the classical corpus

The hollow 其空中

腧穴空虛之處

The hollow of the point, where the qi is felt.

機之動不離其空中 — 靈樞·小鍼解

The mechanism 空中之機

穴中氣機之動

The movement of qi within that hollow.

空中之機清浄以微者 — 靈樞·小鍼解

What one does 密意守氣勿失

得氣之後靜心守之

Once qi is obtained, keep the mind on it and do not lose it.

鍼以得氣，密意守氣勿失也 — 靈樞·小鍼解

Occurrences in the classics

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

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1 passages

靈樞·小鍼解 Read in context →

刺之微在數遲者，徐疾之意也。麤守關者，守四肢而不知血氣正邪之徃來也。上守機者，知守氣也。機之動不離其空中者，知氣之虚實，用鍼之徐疾也。空中之機清浄以微者，鍼以得氣，密意守氣勿失也。其來不可逢者，氣盛不可補也。其徃不可追者，氣虚不可寫也。不可挂以髮者，言氣易失也。扣之不發言者，不知補寫之意也，血氣已盡而氣不下也。刺之微在数迟者，徐疾之意也。麤守关者，守四肢而不知血气正邪之往来也。上守机者，知守气也。机之动不离其空中者，知气之虚实，用针之徐疾也。空中之机清浄以微者，针以得气，密意守气勿失也。其来不可逢者，气盛不可补也。其往不可追者，气虚不可写也。不可挂以发者，言气易失也。扣之不发言者，不知补写之意也，血气已尽而气不下也。

cì zhī wēi zài shuò chí zhě, xú jí zhī yì yě. cū shǒu guān zhě, shǒu sì zhī ér bù zhī xuè qì zhèng xié zhī wǎng lái yě. shàng shǒu jī zhě, zhī shǒu qì yě. jī zhī dòng bù lí qí kōng zhōng zhě, zhī qì zhī xū shí, yòng zhēn zhī xú jí yě. kōng zhōng zhī jī qīng jìng yǐ wēi zhě, zhēn yǐ dé qì, mì yì shǒu qì wù shī yě. qí lái bù kě féng zhě, qì shèng bù kě bǔ yě. qí wǎng bù kě zhuī zhě, qì xū bù kě xiě yě. bù kě guà yǐ fà zhě, yán qì yì shī yě. kòu zhī bù fā yán zhě, bù zhī bǔ xiě zhī yì yě, xuè qì yǐ jǐn ér qì bù xià yě.

The subtlety of needling lies in the slow and the rapid: this is the meaning of slowness and speed. The coarse guard the pass means they guard the four limbs and do not know the coming and going of blood, qi, the upright and the evil. The superior guard the mechanism means they know how to guard the qi. The movement of the mechanism never leaves its hollow means knowing the excess and deficiency of the qi and the slowness or speed of the needle. The mechanism in the hollow, clear and still and subtle, means that the needle has obtained qi, and one keeps the mind closely on the qi and does not lose it. When it comes, do not meet it means that when the qi is abundant one must not supplement. When it has gone, do not pursue it means that when the qi is deficient one must not reduce. Not to be hung by a hair means the qi is easily lost. To strike it and not release means not knowing the meaning of supplementing and reducing: the blood and qi are already exhausted and the qi does not descend.

「空中」本篇2見，「空中之機」1見。「機」字3見，自「上守機」至「機之動」，再至「空中之機」，一線而下；機者弩牙，非器物，故曰「動」，曰「不離」，皆狀其發而未發之際。

Compounds built on this term

守機

shǒu jī

guarding the mechanism

上守機者，知守氣也

氣機

qì jī

the mechanism of qi

後世通名

How it has been translated

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

This site	the mechanism in the hollow	the chapter's own three words, in its own order
Literal	the trigger within the empty	exact, and it is not English
Clinical	the arriving qi at the point	clear, and it decides what the chapter leaves open

Entry status

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2026-10-24

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