Traditional Chinese timekeeping refers to thetime standards for divisions of the day used inChina until the introduction of theShixian calendar in 1628 at the beginning of theQing dynasty.^[1][2]

Dating from theHan dynasty, the third chapter of theHuainanzi outlines 15 hours of daylight. These are dawn (晨明), morning light (朏明), daybreak (旦明), early meal (早食;蚤食), feast meal (宴食), before noon (隅中), noon (正中), short shadow (少还;小還), evening (𫗦时;餔時; 'evening mealtime'), long shadow (大还;大還), high setting (高舂), lower setting(下舂), sunset (县东;縣東), twilight (黄昏;黃昏), rest time (定昏).^[3] These correspond to each hour from 06:00 to 20:00 on the24-hour clock.

The system used between theEastern Han andMing dynasties comprised two standards to measure the time in asolar day. Times during daylight were measured in theshí-kè standard, and at night were measured using thegēng-diǎn standard.

Theshí-kè (時–刻) system is derived fromthe position of the sun.

Eachshí (時;时) was1⁄12 of the time between one midnight and the next,^[2] making it roughly double the modern hour. These dual hours are named after theearthly branches in order, with midnight in the firstshí. This firstshí traditionally occurred from 23:00 to 01:00 on the 24-hour clock, but was changed during theSong dynasty so that it fell from 00:00 to 02:00, with midnight at the beginning.^[2]

Starting from the end of theTang dynasty into the Song dynasty, eachshí was divided in half, with the first half called the initial hour (初) and the second called the central hour (正).^[2] The change of the midnight hour in the Song dynasty could thus be stated as going from the central hour of the firstshí (子正) to the initial hour of the firstshí (子初).

Days were also divided into smaller units, calledkè (刻). Onekè was usually defined as1⁄100 of a day until 1628, though there were short periods before then where days had 96, 108 or 120kè.^[2]kè literally means "mark" or "engraving", referring to the marks placed on sundials^[4] or water clocks^[5] to help keep time.

Using the definition ofkè as1⁄100 of a day, eachkè is equal to 0.24 hours, 14.4 minutes, or 14 minutes 24 seconds. Everyshí contains 81⁄3kè, with 7 or 8 fullkè and partial beginning or endingkè. These fractionalkè are multiples of1⁄6kè, or 2 minutes 24 seconds.^[a] The 7 or 8 fullkè within eachshí were referred to as "majorkè" (大刻). Each1⁄6 of akè was called a "minorkè" (小刻).^[6]

Bothshí andkè were used to describe the time, through one of two ways:

1. Eightkè mode. Before the Tang dynasty, theshí were noted first, then each of the majorkè were counted up to 8.^[6]
   1. As an example, counting by majorkè from the firstshí to the second: zǐ (子), zǐ yī kè (子一刻), zǐ èr kè (子二刻), zǐ sān kè (子三刻), zǐ sì kè (子四刻), zǐ wǔ kè (子五刻), zǐ liù kè (子六刻), zǐ qī kè (子七刻), zǐ bā kè (子八刻), chǒu (丑).
   2. The time xū yī kè (戌一刻) would be read as "1kè afterxū shí", making the time 20:09:36.
2. Fourkè mode. After the Tang dynasty's division of theshí, it was still noted first, but with an added description of which half of theshí thekè was taking place in. Since this narrowed the range of the possible majorkè down to four, it was only necessary to specify the majorkè between one and four.^[6]
   1. This changes the first example above to:zǐ initial (子初),zǐ initial 1 kè (子初一刻),zǐ initial 2 kè (子初二刻),zǐ initial 3 kè (子初三刻),zǐ initial 4 kè (子初四刻),zǐ central^[b] (子正),zǐ central 1 kè (子正一刻),zǐ central 2 kè (子正二刻),zǐ central 3 kè (子正三刻),zǐ central 4 kè (子正四刻),chǒu initial (丑初).
   2. The timesì central 3 kè (巳正三刻) would be read as "the thirdkè in the second half ofsì", corresponding to the time 11:31:12.

kè were subdivided into smaller units, calledfēn (分). The number offēn in eachkè varied over the centuries,^[2] but afēn was generally defined as1⁄6000 of a day.^[6] Using this definition, onefēn is equal to 14.4 seconds. This also means that afēn is1⁄60 of a majorkè and1⁄10 of a minorkè.

In 1280,Guo Shoujing's Shòushí Calendar (授时曆) subdivided eachfēn into 100miǎo (秒).^[7] Using the definition offēn as 14.4 seconds, eachmiǎo was 144 milliseconds long.

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In Buddhism, eachfen was subdivided intoshùn (瞬), andshùn were subdivided intoniàn (念).

TheMahāsāṃghika, translated into Chinese as theMóhēsēngzhī Lǜ (Taishō Tripiṭaka 1425) describes several units of time, includingshùn orshùnqǐng (瞬頃; 'blink moment') andniàn. According to this text,niàn is the smallest unit of time at 18 milliseconds and ashùn is 360 milliseconds.^[8] It also describes larger units of time, including atánzhǐ (彈指) which is 7.2 seconds long, aluóyù (羅豫) which is 2 minutes 24 seconds long, and axūyú (須臾), which is1⁄30 of a day at 48 minutes long.^[c]

TheGēng-diǎn (更–點) system uses predetermined signals to define the time during the night.

Gēng (更) is a time signal given by drum or gong. The drum was sounded by thedrum tower in city centers, and by night watchman hitting a gong in other areas.^{[citation needed]} The character forgēng更, literally meaning "rotation" or "watch", comes from the rotation of watchmen sounding these signals.

The firstgēng theoretically comes at sundown, but was standardized to fall atyǒu shí central 1kè, or 19:12. The time between eachgēng is1⁄10 of a day, making agēng 2.4 hours—or 2 hours 24 minutes—long.

The 5gēngs in the night are numbered from one to five:yì gēng (一更) (alternatelychū gēng (初更) for "initial watch");èr gēng (二更);sān gēng (三更);sì gēng (四更); andwǔ gēng (五更). The 5 gēngs in daytime are named after times of day listed in theBook of Sui, which describes the legendaryYellow Emperor dividing the day and night into ten equal parts. They are morning (朝); midmorning, (禺); noon, (中); afternoon (晡); and evening (夕).^[9]

As a 10-part system, thegēng are strongly associated with the 10celestial stems, especially since the stems are used to count off thegēng during the night in Chinese literature.^[9]

Diǎn (点;點), or point, marked when the bell time signal was rung. The time signal was released by the drum tower or local temples.^{[citation needed]}

Eachdiǎn or point is1⁄60 of a day, making them 0.4 hours, or 24 minutes, long. Every sixthdiǎn falls on thegēng, with the rest evenly dividing everygēng into 6 equal parts.

Gēng and diǎn were used together to precisely describe the time at night.

Counting from the firstgēng to the next would look like this:yìgēng (一更),yìgēng 1 diǎn (一更一点;一更一點),yìgēng 2 diǎn (一更二点;一更二點),yìgēng 3 diǎn (一更三点;一更三點),yìgēng 4 diǎn (一更四点;一更四點),yìgēng 5 diǎn (一更五点;一更五點),èrgēng (二更).

Given the timesāngēng 2 diǎn (三更二点;三更二點), you would read it as "twodiǎn aftersāngēng", and find the time to be 00:48.^[d]

The night length is inconsistent during a year. The nineteenth volume of theBook of Sui says that at the winter solstice, a day was measured to be 60% night, and at the summer solstice, only 40% night.^[10] The official start of night thus had a variation from 0 to 1gēng.

This variation was handled in different ways. From the start of theWestern Han dynasty in 206 BC until 102 AD,yìgēng was moved back onekè every 9th day from the winter solstice to the summer solstice, and moved forward onekè every 9th day from summer solstice to the winter solstice.^[10] The Xia Calendar (夏历;夏曆), introduced in 102 AD, added or subtracted akè to the start of night whenever the sun moved 2.5° north or south from its previous position.^[10]

Chinese still uses characters from these systems to describe time, even though China has changed to theUTC standards of hours, minutes, and seconds.

shí is still used to describe the hour. Because of the potential for confusion,xiǎoshí (小时;小時, literally "small hour") is sometimes used for the hour as part of a 24-hour cycle, andshíchen (时辰;時辰) is used for the hour as part of the old 12-hour cycle.Diǎn is also used interchangeably withshí for the hour. It can also be used to talk about the time on the hour—for example, 8 o' clock is written as 8diǎn (八点;八點).

Fēn is now the standard term for the minute. Sometimes the wordfēnzhōng (分钟;分鐘; 'clock minute') is used to clarify that one is talking about modern minutes. The time 09:45 can thus be written as "9shí, 45fēn" (九时四十五分;九時四十五分) or "9diǎn, 45fēn" (九点四十五分;九點四十五分).

kè has been defined as1⁄96 of a day since 1628, so the modernkè equals 15 minutes and each double hour contains exactly 8kè.^[2] Since then,kè has been used as shorthand to talk about time in1⁄8 of a double hour or1⁄4 of a single hour. Their usage is similar to using "quarter hour" for 15 minutes or "half an hour" for 30 minutes in English. For example, 6:45 can be written as "6diǎn, 3kè" (六点三刻;六點三刻).

Miǎo is now the standard term for a second. Likefēn, it is sometimes written asmiǎozhōng (秒钟;秒鐘; 'clock second') to clarify that someone is talking about modern seconds.

• Chinese Buddhism, the texts from which the smallest units of traditional Chinese time are derived
• Chinese calendar
• Chinese units of measurement
• Date and time notation in Asia
• Decimal time
• Hour

• Ronan, Colin (1999). "Astronomy in China, Korea and Japan". In Christopher Walker (ed.).Astronomy before the telescope. London: British Museum Press. pp. 247–250.ISBN 0-7141-2733-7.
• Stephenson, F. Richard (1997).Historical Eclipses and Earth's Rotation. Cambridge: Cambridge University Press.ISBN 9780521461948.

• Astronomy in China
• Specific calendars
• Metrication
• Decimal time
• Time measurement systems
• Units of time
• Timekeeping

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• Short description is different from Wikidata
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