日乘四季

rì chéng sì jì

Riding the four quarters of the year · ri cheng si ji

Also rendered: riding the four quarters of the year (Literal, and keeps 乘 as a mounting) · on a day at the seasonal turns (Explanatory rather than translational) · in the four seasons' last days (Reads 四季 as the four seasons themselves) · ri cheng si ji (Bare transliteration)

Cosmology

Reviewed · 2026-09

At a glance

Pinyin: rì chéng sì jì
Simplified: 日乘四季
Literal: 乘 to mount, to ride upon (《說文》: 乘，覆也 — to cover from above; 段注: 引申之凡憑乘、覆載皆曰乘). 四季 the four quarters of the year. A day that rides them: the death-hour assigned to a pulse that cannot settle, one that is now scattered and now rapid, now slow and now swift.
Shuowen: 《說文解字》：乘，覆也（段玉裁注：覆者，蓋也；引申之凡憑乘、乘載皆曰乘）。

In brief

The last and strangest of the chapter’s death-hours. The chapter assigns an hour to each kind of pulse: the cold-heat disease dies at dawn, heat in the centre and heat disease at midday, wind disease at dusk, water disease at midnight. But the pulse that is 乍疏乍數、乍遲乍疾 — scattered, then rapid, slow, then swift, never settling — gets no hour at all; it dies on a day that rides the four quarters of the year. The phrase is usually taken as the four turning-points, the eighteen days at the end of each season when one quarter is handing over to the next, and the reading fits: a pulse with no fixed rate is given a time with no fixed season.

Senses in the classical corpus

The pulse it belongs to 乍疏乍數，乍遲乍疾

或疏或數，或遲或疾，無定

其脉乍疏乍數，乍遲乍疾者，日乘四季死 — Suwen 20

The hours named before it 平旦、日中、日夕、夜半

寒熱平旦，熱中日中，風日夕，水夜半

是故寒熱病者，以平旦死。熱中及熱病者，以日中死。病風者，以日夕死。病水者，以夜半死 — Suwen 20

Why this one has no hour 無定之脈，不繫於一時

脈無定候，故不以一時決之

其脉乍疏乍數，乍遲乍疾者，日乘四季死 — Suwen 20

The seasons behind the phrase 四季

四季之交，各季之末十八日

其脉乍疏乍數，乍遲乍疾者，日乘四季死 — Suwen 20

How it sits in the chapter 冬陰夏陽

本篇以晝夜陰陽配死時，此則推之於四季

帝曰：冬陰夏陽，奈何 — Suwen 20

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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2 passages

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

是故寒熱病者，以平旦死。熱中及熱病者，以日中死。病風者，以日夕死。病水者，以夜半死。其脉乍疏乍數，乍遲乍疾者，日乘四季死。是故寒热病者，以平旦死。热中及热病者，以日中死。病风者，以日夕死。病水者，以夜半死。其脉乍疏乍数，乍迟乍疾者，日乘四季死。

Shì gù hán rè bìng zhě, yǐ píng dàn sǐ. Rè zhōng jí rè bìng zhě, yǐ rì zhōng sǐ. Bìng fēng zhě, yǐ rì xī sǐ. Bìng shuǐ zhě, yǐ yè bàn sǐ. Qí mài zhà shū zhà shuò, zhà chí zhà jí zhě, rì chéng sì jì sǐ.

Thus cold-heat disease kills at daybreak; internal heat and heat disease kill at noon; wind disease kills at sunset; water disease kills at midnight. One whose pulse is now scattered, now rapid, now slow, now hurried dies on a day that mounts the four quarters of the year.

本篇以脈之陰陽定死時：九候皆沈細懸絶者為陰主冬，以夜半死；盛躁喘數者為陽主夏，以日中死。推之則寒熱病以平旦死，熱中及熱病以日中死，病風以日夕死，病水以夜半死；獨「乍疏乍數、乍遲乍疾」之脈無定時，故不言某時而言「日乘四季」——舊說四季謂四季之交、各季之末，其時屬土而無專令，以應此脈之無定候。與第十九篇「一日一夜五分之，此所以占死生之早暮也」同為以時占死之法，而彼以晝夜五分，此則推及四季。

素問·藏氣法時論 Suwen 22 · 藏氣法時論 Read in context →

腎病者，夜半慧，四季甚，下晡靜。肾病者，夜半慧，四季甚，下晡静。

Shèn bìng zhě, yè bàn huì, sì jì shèn, xià bū jìng.

In kidney illness the patient is clear at midnight, worse at the four last months of the seasons, and quiet in the late afternoon.

「腎病者，夜半慧，四季甚，下晡靜」：本篇四季之義，謂辰戌丑未四個月——四季之末各十八日屬土，土盛乘水，故腎病至此而甚。與第二十篇「日乘四季而死」者同條而義別：第二十篇以之定死期之辰，本篇則以之為腎病加重之時；所指之季同一，而一決死、一言甚。

Compounds built on this term

乘

chéng

to ride upon

說文：覆也

四季

sì jì

the four quarters of the year

四時之交，季末之時

乍疏乍數

zhà shū zhà shuò

now scattered, now rapid

數音 shuò

乍遲乍疾

zhà chí zhà jí

now slow, now swift

疾與遲對

夜半

yè bàn

midnight

本篇水病之死時

How it has been translated

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

Wiseman & Feng	(no fixed rendering; 乘 is rendered as mounting or riding where it describes evil qi)	The phrase is rare and is usually glossed in commentary rather than named.
Unschuld	[dies] when the day reaches the four seasons	He leaves 乘 untranslated in effect, letting the day do the moving.
This site	riding the four quarters of the year	乘 in 說文 is 覆 — to cover from above — which is why the word can mean both to ride and to take advantage of: something is on top of something else. Keeping it as riding preserves that the day is doing something to the season, not merely sitting in it, and it lets the two things the phrase is usually taken to mean stay together — the day of one of the four seasonal turning-points, and a day that has climbed onto all four because the pulse beneath it will not hold still.

Entry status

Review pending — who reviews this?

2026-09

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