Shichen to Seconds (shichen to s)
1 shichen equals 7,200 seconds exactly.
How to convert shichen to seconds
To convert shichen to seconds, multiply the number of shichen by 7,200. This factor is exact. To go the other way, multiply seconds by 0.0001388888889 (rounded).
seconds = shichen × 7,200
Example: 10 shichen = 72,000 seconds.
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
Shichen (shichen)
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
Second (s)
The SI base unit of time, defined by the radiation frequency of the cesium-133 atom: 9,192,631,770 cycles per second.
Our word second is a leftover of Latin. Medieval scholars divided a degree, and later the hour, into 60 parts called pars minuta prima, the first small part, and divided those again into pars minuta secunda, the second small part. NIST traces the roots further back: Babylonian and Greek astronomers split the circle into 360 degrees, and around 150 C.E. Ptolemy split each degree into 60 minutes and each minute into 60 seconds. Clocks that could show seconds appeared only in the later 16th century, and Christiaan Huygens's pendulum clock of 1656 was the first able to keep time accurately to the second.
For most of history the second was a fraction of a day, and in 1956 it was redefined as a fraction of the tropical year, a definition the SI took over in 1960. In 1967 the 13th CGPM switched to atoms: 9,192,631,770 periods of the radiation tied to a hyperfine transition of caesium-133. The 2019 SI revision restated this by fixing the caesium frequency at 9,192,631,770 hertz. NIST reports that commercial caesium clocks stay within about a three-millionth of a second per year, and experimental clocks based on other atoms are roughly ten thousand times more precise.
The second is the reference unit for time on this site.
Sources: NIST: the second and the SI redefinition; BIPM: SI Brochure, 9th edition; Wikipedia: Second
Related conversions
- Seconds to shichen (reverse)
- Shichen to minutes
- Shichen to hours
- Shichen to days
- Shichen to weeks
- Shichen to months
- Shichen to years
- Minutes to seconds
- Hours to seconds
- Days to seconds
- Weeks to seconds
- Months to seconds
- Years to seconds
- Milliseconds to seconds
- Microseconds to seconds
- Nanoseconds to seconds
- Decades to seconds
- Centuries to seconds
- Millennia to seconds
See all time units.