Chinese Hours
The Chinese day is divided into twelve double hours, or shichen, each named after an animal. Their boundaries follow the Sun, not the clock on the wall, so in Moscow the Horse hour begins not at 11:00 but at around 11:30. The calculator converts clock time into a Chinese hour for any city.
The Twelve Hours
The day is divided into twelve shichen of two hours each. The times in the table are true solar time: at noon the Sun stands in the middle of the Horse hour.
Why the Sun and Not the Clock
Time zones appeared in the 19th century; Chinese hours are millennia older and follow the Sun. To convert clock time into solar time, you need two corrections.
- For longitude. Each degree east of the middle of the time zone adds four minutes, and each degree west subtracts four. Moscow, at 37.6° E, runs on the time of the 45th meridian, so the Sun there lags behind the clock by about half an hour.
- The equation of time. Because of the tilt of Earth's axis and its elongated orbit, solar noon drifts by ±16 minutes over the year: in early November the Sun runs fast, and in mid-February it runs slow.
The calculator applies both corrections and accounts for historical time zones, so it also works for a date of birth: this is exactly how the hour is determined in BaZi.
The Rat Hour and the Change of Day
The Rat hour, from 23:00 to 01:00 solar time, straddles two days. In Chinese tradition the new day begins with it, at 23:00, so after 23:00 the hour pillar is already counted from the next day. Some schools split this hour in two and change the day at midnight; you can choose this option in the BaZi calculator.
Frequently asked questions
What Chinese hour is it right now?
When it opens, the calculator fills in the current date and time. Choose your city, and it will show the Chinese hour based on the position of the Sun.
Why do I need to choose a city?
Solar time depends on longitude: in Kaliningrad and in Vladivostok, the same clock time falls in different solar hours.