Hours to Shichen (h to shichen)

1 hour equals 0.5 shichen exactly.

1 hour = 0.5 shichen

How to convert hours to shichen

To convert hours to shichen, multiply the number of hours by 0.5. This factor is exact. To go the other way, multiply shichen by 2.

shichen = hours × 0.5

Example: 10 hours = 5 shichen.

Months and years are not constant. This site uses the average Gregorian year of 365.2425 days, so one 'year' converts to 365.2425 days, not 365; use 'common year' for exactly 365 days.

About these units

Hour (h)

Metric (SI)Current unit

60 minutes or 3,600 seconds, one twenty-fourth of a mean solar day.

Egyptian astronomers gave us the twelve. Coffin lids from about 2150 BC show the night divided into exactly 12 intervals, tied to the rising of star groups called decans, and the day was later split into 12 hours with sundials. These were seasonal hours, a twelfth of the daylight, so a summer hour was longer than a winter one. The word itself comes from Greek hora, originally any span of time, through Latin and Old French into English in the 13th century.

Equal hours of 1/24 of a day were probably first proposed by Hipparchus, and mechanical clocks made them the practical choice, since a clock showing seasonal hours had to be readjusted every morning and evening. Today the hour is exactly 3,600 seconds and is a non-SI unit accepted for use with the SI. Civil time still bends it a little: UTC hours have lasted 3,601 seconds 27 times since 1972 to keep clocks within 0.9 seconds of the Earth's rotation. In practice we use it for working shifts, travel times and electricity bills measured in kilowatt-hours.

1 hour = 3,600 seconds (exactly).

Sources: Wikipedia: Hour; BIPM: SI Brochure, 9th edition

Shichen (shichen)

ChineseHistorical unit (no longer in standard use)

The traditional Chinese 'double hour': two hours, twelve per day, each named after an animal of the zodiac.

Chinese clocks did not always count 24 hours. Since the Han dynasty the day has been divided into twelve periods named after the Earthly Branches, each lasting two hours and called a shichen. The first, zi, runs from 23:00 to 01:00 and is linked to the rat, followed by ox, tiger, rabbit, dragon, snake, horse, goat, monkey, rooster, dog and pig. The animal marks the centre of its period, so the horse sits at noon.

The animals were a practical shorthand, since the branch characters were easy to confuse, as the Eastern Han scholar Xu Shen noted. A Sui dynasty Buddhist text even gave each shichen three animals, one for morning, midday and evening. In the figure used here a shichen is exactly one twelfth of a day, or 7,200 seconds. The same twelve branches also name the years of the zodiac cycle.

1 shichen = 7,200 seconds (exactly).

Sources: Wikipedia: Chinese zodiac; Wikipedia: Chinese units of measurement

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