虚

xū

The empty quality · xu

Also rendered: The vacuous pulse (Literal) · The deficient pulse (Clinical)

Reviewed · 2026-10-28

At a glance

Pinyin
xū
Simplified
虚
Literal
虚 xū — a great mound once inhabited and now hollow; hence emptiness, the lack of what should be there. As a pulse it is soft, without resistance, and it yields under the finger.
Shuowen
**《說文》:虛,大丘也**,从丘,虍聲;**「虚」為其省文**,底本通用「虚」。**「虚」五篇共39見**(經文),其為脉名者,多見於「芤則爲虚」「浮則爲虚」「脉虚身熱」三處。

In brief

The empty quality: a pulse without substance, yielding under the finger because what should fill it is not there. The book names it twice by derivation — the hollow pulse is empty (芤則爲虚), and a floating pulse at the instep is empty (浮則爲虚) — and once by the body it accompanies: 脉虚身熱,得之傷暑, an empty pulse with a hot body comes from summerheat. Emptiness here is not one shape but a conclusion drawn from shape plus circumstance.

Senses in the classical corpus

1
The hollow pulse is empty 芤則爲虚
芤脉中空,故主虚
Large becomes hollow, diminished becomes cold, and hollow means empty.
大則爲芤,減則爲寒,芤則爲虚 — 傷寒論·辨脉法第一
2
Floating is empty 浮則爲虚
趺陽脉浮,浮主胃氣虚竭
At the instep a floating pulse means emptiness: the stomach qi is exhausted and qi is blocked.
趺陽脉浮,浮則爲虚 — 傷寒論·辨脉法第一
3
An empty pulse with a hot body 脉虚身熱
脉虚而身熱,得之傷暑
An empty pulse with a hot body comes from summerheat; a full pulse with a cold body comes from cold damage.
脉虚身熱,得之傷暑 — 傷寒論·傷寒例第三
4
Both sides empty 脉陰陽俱虚
陰陽俱虚而熱不止者死
When both yin and yang pulses are empty and the heat will not stop, death follows.
脉陰陽俱虚,熱不止者死 — 傷寒論·傷寒例第三
5
Empty within, replete without 名曰内虚外實也
來疾去遲,是内虚外實
Coming quickly and leaving slowly, the pulse is empty within and replete without.
來疾去遲,此出疾入遲,名曰内虚外實也 — 傷寒論·平脉法第二
6
The man sick, the pulse not 人病脉不病,名曰内虚
人病而脉不病,是内虚
When the man is sick and the pulse is not, it is called inner emptiness: there is no grain spirit.
人病脉不病,名曰内虚 — 傷寒論·平脉法第二

Occurrences in the classics

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

Display
5 passages
傷寒論·辨脉法第一 Read in context →
脉弦而大,弦則爲減,大則爲芤,減則爲寒,芤則爲虚,寒虚相摶,此名爲革。婦人則半産漏下,男子則亡血失精。 脉弦而大,弦则为减,大则为芤,减则为寒,芤则为虚,寒虚相抟,此名为革。妇人则半产漏下,男子则亡血失精。
mài xián ér dà xián zé wéi jiǎn dà zé wéi kōu jiǎn zé wéi hán kōu zé wéi xū hán xū xiāng tuán cǐ míng wéi gé fù rén zé bàn chǎn lòu xià nán zǐ zé wáng xuè shī jīng
A pulse wiry and large: wiry means diminished, large means hollow, diminished means cold, hollow means vacuous; cold and vacuity striking together is called the leather pulse. In women it brings miscarriage and dripping menses, in men the loss of blood and semen.
**「虚」五篇共39見**(經文,不含成注),本文引第1篇第18段、第1篇第41段、第3篇第53段、第2篇第09段、第2篇第39段。
傷寒論·辨脉法第一 Read in context →
趺陽脉浮,浮則爲虚,浮虚相搏,故令氣䭇,言胃氣虚竭也。脉滑則爲噦,此爲醫咎,責虚取實,守空迫血。脉浮,鼻中燥者,必衄也。 趺阳脉浮,浮则为虚,浮虚相搏,故令气䭇,言胃气虚竭也。脉滑则为哕,此为医咎,责虚取实,守空迫血。脉浮,鼻中燥者,必衄也。
fū yáng mài fú fú zé wéi xū fú xū xiāng bó gù lìng qì yē yán wèi qì xū jié yě mài huá zé wéi yuě cǐ wéi yī jiù zé xū qǔ shí shǒu kōng pò xuè mài fú bí zhōng zào zhě bì nǜ yě
When the fuyang pulse is floating, floating means vacuity; floating and vacuity striking together produce choking of qi, which is to say the stomach qi is vacuous and exhausted. A slippery pulse means hiccough; this is the physician’s fault, exacting from vacuity and taking from excess, guarding emptiness and driving the blood. If the pulse is floating and the nose dry, there will certainly be nosebleed.
虚非一形:芤之空、浮之無力、身熱而脉虚,三者皆謂之虚,當合形與證觀之。
傷寒論·傷寒例第三 Read in context →
脉盛身寒,得之傷寒;脉虚身熱,得之傷暑。 脉盛身寒,得之伤寒;脉虚身热,得之伤暑。
mài shèng shēn hán dé zhī shāng hán mài xū shēn rè dé zhī shāng shǔ
A full pulse with a cold body comes from cold damage; a vacuous pulse with a hot body comes from summer-heat damage.
虚非一形:芤之空、浮之無力、身熱而脉虚,三者皆謂之虚,當合形與證觀之。
傷寒論·平脉法第二 Read in context →
初持脉,來疾去遲,此出疾入遲,名曰内虚外實也。初持脉,來遲去疾,此出遲入疾,名曰内實外虚也。 初持脉,来疾去迟,此出疾入迟,名曰内虚外实也。初持脉,来迟去疾,此出迟入疾,名曰内实外虚也。
chū chí mài lái jí qù chí cǐ chū jí rù chí míng yuē nèi xū wài shí yě chū chí mài lái chí qù jí cǐ chū chí rù jí míng yuē nèi shí wài xū yě
When first feeling the pulse, if it comes quickly and leaves slowly, this is quick coming out and slow going in, named inner vacuity and outer repletion. If it comes slowly and leaves quickly, this is slow coming out and quick going in, named inner repletion and outer vacuity.
虚非一形:芤之空、浮之無力、身熱而脉虚,三者皆謂之虚,當合形與證觀之。
傷寒論·平脉法第二 Read in context →
師曰:脉病人不病,名曰行尸,以無王氣,卒眩仆不識人者,短命則死。人病脉不病,名曰内虚,以無穀神,雖困無苦。 师曰:脉病人不病,名曰行尸,以无王气,卒眩仆不识人者,短命则死。人病脉不病,名曰内虚,以无谷神,虽困无苦。
shī yuē mài bìng rén bù bìng míng yuē xíng shī yǐ wú wàng qì cù xuàn pū bù shí rén zhě duǎn mìng zé sǐ rén bìng mài bù bìng míng yuē nèi xū yǐ wú gǔ shén suī kùn wú kǔ
The Master said: “When the pulse is diseased but the person is not, it is called a walking corpse, for there is no flourishing qi; when sudden dizziness and falling senseless come, life is short and ends. When the person is diseased but the pulse is not, it is called inner vacuity, for there is no grain spirit; though he is distressed, he suffers no harm.”
虚非一形:芤之空、浮之無力、身熱而脉虚,三者皆謂之虚,當合形與證觀之。

Compounds built on this term

芤則爲虚
kōu zé wéi xū
hollow means empty
辨脉法第一
浮則爲虚
fú zé wéi xū
floating means empty
辨脉法第一
脉虚身熱
mài xū shēn rè
an empty pulse with a hot body
傷寒例第三
内虚外實
nèi xū wài shí
empty within, replete without
平脉法第二

How it has been translated

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

This sitethe empty qualityan observation, not yet a diagnosis
Literalhollowoverlaps the hollow pulse, which is 芤
Clinicaldeficientclear, and it decides what the text leaves open

Entry status

Review pending — who reviews this?

2026-10-28

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Reading path

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