Traditional Chinese timekeeping refers to the time standards for divisions of the day used in China until the introduction of the Shixian calendar in 1644 at the beginning of the Qing dynasty.

Han-era system Dating from the Han dynasty, the third chapter of the Huainanzi outlines 15 hours of daylight. These are dawn (), morning light (), daybreak (), early meal (), feast meal (), before noon (), noon (), short shadow (), evening (), long shadow (), high setting (), lower setting(), sunset (), twilight (), rest time (). These correspond to each hour from 06:00 to 20:00 on the 24-hour clock.

Eastern Han to Ming system The system used between the Eastern Han and Ming dynasties comprised two standards to measure the time in a solar day. Times during daylight were measured in the standard, and at night were measured using the standard.

+ Stems and branches in traditional Chinese timeHeavenly stemsEarthly branches Stem Gēng Branch Shí(traditional) Shí(Song dynasty)119:12123:0000:00221:36201:0002:003 00:00303:0004:00402:24405:0006:00504:48507:0008:00607:12morning609:0010:00709:36midmorning711:0012:00812:00noon813:0014:00914:24late afternoon915:0016:001016:48evening1017:0018:001119:0020:001221:0022:00

During daylight: shí-kè The ( – ) system is derived from the position of the sun.

Dual hour: shí Each was of the time between one midnight and the next, making it roughly double the modern hour. These dual hours are named after the earthly branches in order, with midnight in the first . This first traditionally occurred from 23:00 to 01:00 on the 24-hour clock, but was changed during the Song dynasty so that it fell from 00:00 to 02:00, with midnight at the beginning.

Starting from the end of the Tang dynasty into the Song dynasty, each was divided in half, with the first half called the initial hour () and the second called the central hour (). The change of the midnight hour in the Song dynasty could thus be stated as going from the central hour of the first () to the initial hour of the first ().

One-hundredth of a day: kè Days were also divided into smaller units, called . One was usually defined as of a day until 1628, though there were short periods before then where days had 96, 108 or 120 . literally means "mark" or "engraving", referring to the marks placed on sundials or water clocks to help keep time.

Using the definition of as of a day, each is equal to 0.24 hours, 14.4 minutes, or 14 minutes 24 seconds. Every contains 8 , with 7 or 8 full and partial beginning or ending . These fractional are multiples of , or 2 minutes 24 seconds. The 7 or 8 full within each were referred to as "major " (). Each of a was called a "minor " ().

Describing the time during daylight Both and were used to describe the time, through one of two ways: Eight mode. Before the Tang dynasty, the were noted first, then each of the major were counted up to 8. As an example, counting by major from the first to the second: , , , , , , , , , . The time would be read as "1 after ", making the time 19:14:24. Four mode. After the Tang dynasty's division of the , it was still noted first, but with an added description of which half of the the was taking place in. Since this narrowed the range of the possible major down to four, it was only necessary to specify the major between one and four. This changes the first example above to: initial (), initial 1 (), initial 2 (), initial 3 (), initial 4 (), central (), central 1 (), central 2 (), central 3 (), central 4 (), initial (). The time central 3 () would be read as "the third in the second half of ", corresponding to the time 11:31:12.

Smaller time units Fēn were subdivided into smaller units, called . The number of in each varied over the centuries, but a fēn was generally defined as of a day. Using this definition, one is equal to 14.4 seconds. This also means that a is of a major and of a minor .

Miǎo In 1280, Guo Shoujing's Shòushí Calendar () subdivided each into 100 . Using the definition of fēn as 14.4 seconds, each miǎo was 144 milliseconds long.

Shùn and niàn

In Buddhism, each was subdivided into , and were subdivided into .

The Mahāsāṃghika, translated into Chinese as the Móhēsēngzhī Lǜ (Taishō Tripiṭaka 1425) describes several units of time, including or () and . According to this text, is the smallest unit of time at 18 milliseconds and a is 360 milliseconds. It also describes larger units of time, including a which is 7.2 seconds long, a which is 2 minutes 24 seconds long, and a , which is of a day at 48 minutes long.

During night: gēng-diǎn system The ( – ) system uses predetermined signals to define the time during the night.

One-tenth of a day: gēng is a time signal given by drum or gong. The drum was sounded by the drum tower in city centers, and by night watchman hitting a gong in other areas. The character for , literally meaning "rotation" or "watch", comes from the rotation of watchmen sounding these signals.

The first theoretically comes at sundown, but was standardized to fall at central 1 , or 19:12. The time between each is of a day, making a 2.4 hours—or 2 hours 24 minutes—long.

The 5 in the night are numbered from one to five: (alternately for "initial watch"); ; ; ; and . The 5 gēngs in daytime are named after times of day listed in the Book of Sui, which describes the legendary Yellow Emperor dividing the day and night into ten equal parts. The during daytime are morning (); midmorning, (); noon, (); afternoon (); and evening ().

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

One-sixtieth of a day: Diǎn (), or point, marked when the bell time signal was rung. The time signal was released by the drum tower or local temples.

Each or point is of a day, making them 0.4 hours, or 24 minutes, long. Every sixth falls on the , with the rest evenly dividing every into 6 equal parts.

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

Counting from the first to the next would look like this: , , , , , , . Given the time , you would read it as "two after ", and find the time to be 00:48.

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

This variation was handled in different ways. From the start of the Western Han dynasty in 206 BC until 102 AD, was moved back one every 9th day from the winter solstice to the summer solstice, and moved forward one every 9th day from summer solstice to the winter solstice. The Xia Calendar (), introduced in 102 AD, added or subtracted a to the start of night whenever the sun moved 2.5° north or south from its previous position.

Traditional units in context Relationships between traditional Chinese time units00:00:0000:24:00 1 00:48:00 2 01:12:00 3 01:36:00 4 02:00:00 5 02:24:0002:48:00 1 03:12:00 2 03:36:00 3 04:00:00 4 04:24:00 5 04:48:0005:12:00 1 05:36:00 2 06:00:00 3 06:24:00 4 06:48:00 5 07:12:00Morning07:36:00Morning 1 08:00:00Morning 2 08:24:00Morning 3 08:48:00Morning 4 09:12:00Morning 5 09:36:00Midmorning10:00:00Midmorning 1 10:24:00Midmorning 2 10:48:00Midmorning 3 diǎn11:12:00Midmorning 4 11:36:00Midmorning 5 12:00:00Noon12:24:00Noon 1 12:48:00Noon 2 13:12:00Noon 3 13:36:00Noon 4 14:00:00Noon 5 14:24:00Afternoon14:48:00Afternoon 1 15:12:00Afternoon 2 15:36:00Afternoon 3 16:00:00Afternoon 4 16:24:00Afternoon 5 16:48:00Evening17:12:00Evening 1 17:36:00Evening 2 18:00:00Evening 3 18:24:00Evening 4 18:48:00Evening 5 19:12:0019:36:00 1 20:00:00 2 20:24:00 3 20:48:00 4 21:12:00 5 21:36:0022:00:00 1 22:24:00 2 22:48:00 3 23:12:00 4 23:36:00 5 00:00:0002:24:0004:48:0007:12:00Morning09:36:00Midmorning12:00:00Noon14:24:00Afternoon16:48:00Evening19:12:0021:36:00 (only major )00:00:0000:14:2400:28:4800:43:1200:57:3601:12:0001:26:2401:40:4801:55:1202:09:3602:24:0002:38:2402:52:4803:07:1203:21:3603:36:0003:50:2404:04:4804:19:1204:33:3604:48:0005:02:2405:16:4805:31:1205:45:3606:00:0006:14:2406:28:4806:43:1206:57:3607:12:0007:26:2407:40:4807:55:1208:09:3608:24:0008:38:2408:52:4809:07:1209:21:3609:36:0009:50:2410:04:4810:19:1210:33:3610:48:0011:02:2411:16:4811:31:1211:45:3612:00:0012:14:2412:28:4812:43:1212:57:3613:12:0013:26:2413:40:4813:55:1214:09:3614:24:0014:38:2414:52:4815:07:1215:21:3615:36:0015:50:2416:04:4816:19:1216:33:3616:48:0017:02:2417:16:4817:31:1217:45:3618:00:0018:14:2418:28:4818:43:1218:57:3619:12:0019:26:2419:40:4819:55:1220:09:3620:24:0020:38:2420:52:4821:07:1221:21:3621:36:0021:50:2422:04:4822:19:1222:33:3622:48:0023:02:2423:16:4823:31:1223:45:36 (post-Tang)00:00:00 initial01:00:00 central02:00:00Chǒu initial03:00:00 central04:00:00 initial05:00:00 central06:00:00 initial07:00:00 central08:00:00 initial09:00:00 central10:00:00 initial11:00:00 central12:00:00 initial13:00:00 central14:00:00 initial15:00:00 central 16:00:00 initial 17:00:00 central18:00:00 initial19:00:00 central20:00:00 initial 21:00:00 central22:00:00 initial 23:00:00 central (ancient)00:00:0001:00:0003:00:0005:00:0007:00:0009:00:0011:00:0013:00:00 15:00:0017:00:00 19:00:00 21:00:00 23:00:00

Modern applications

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

is still used to describe the hour. Because of the potential for confusion, is sometimes used for the hour as part of a 24-hour cycle, and is used for the hour as part of the old 12-hour cycle. is also used interchangeably with for the hour. It can also be used to talk about the time on the hour—for example, 8 o' clock is written as 8 ().

is now the standard term for the minute. Sometimes the word is used to clarify that one is talking about modern minutes. The time 09:45 can thus be written as "9 , 45 " () or "9 , 45 " ().

has been defined as of a day since 1628, so the modern equals 15 minutes and each double hour contains exactly 8 . Since then, has been used as shorthand to talk about time in of a double hour or 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 "6 , 3 " ().

is now the standard term for a second. Like , it is sometimes written as to clarify that someone is talking about modern seconds.

See also 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

Notes

References

Bibliography