十二时辰 · twelve branches across one day
The twelve double hours
Each Earthly Branch names a two-hour period. The animal is its memorable label; the branch is the chart coordinate. Rat opens the sequence at 23:00, and Pig closes it at 22:59 the following evening.
Twenty-four civil hours · twelve branch positions
Find the branch that holds a birth time
Open any record for its clock edges, five possible hour stems, linked month and direction coordinates, and the boundary convention that matters there.
- 01子Rat hourZi · the hour rats are boldest, when a still household is theirs23:00–00:59
- 02丑Ox hourChou · the hour oxen chew the cud, long before the ploughing begins01:00–02:59
- 03寅Tiger hourYin · the hour tigers hunt, the most dangerous stretch of the night03:00–04:59
- 04卯Rabbit hourMao · the hour of the jade rabbit, which the moon was said to hold as it set05:00–06:59
- 05辰Dragon hourChen · the hour dragons were said to fly and make the morning rain07:00–08:59
- 06巳Snake hourSi · the hour snakes leave their burrows without troubling anyone09:00–10:59
- 07午Horse hourWu · noon, when the sun stands highest and yang is at its fullest11:00–12:59
- 08未Goat hourWei · the hour goats graze best, after the worst of the heat13:00–14:59
- 09申Monkey hourShen · the hour monkeys grow lively and call across the trees15:00–16:59
- 10酉Rooster hourYou · the hour hens come home to roost as the light goes17:00–18:59
- 11戌Dog hourXu · the hour dogs take up guard over the household19:00–20:59
- 12亥Pig hourHai · the hour pigs sleep most soundly, when the house has gone quiet21:00–22:59
One fixed half · one moving half
The clock fixes the branch, not the whole pillar
Everyone born in the Tiger period receives the Tiger branch in the hour position, but not everyone receives the same hour stem. The 五鼠遁 rule derives that stem from the day stem, producing one of five valid stem–branch pairs for each clock period.
The branch answers “when in the day?”
Its position, animal, fixed phase, direction and branch relationships do not change. They belong to the same twelve-step system used for months and compass sectors.
The stem connects the hour to the chart
Its phase and polarity move with the Day Master. That is why an hour-animal lookup is useful, but still incomplete as a Four Pillars reading.
The only period that wraps midnight
Rat hour makes the day boundary visible
23:00–00:59 crosses the Gregorian date line. Some Four Pillars schools let the new sexagenary day begin at 23:00; others retain civil midnight. A 23:xx birth can therefore produce two internally consistent day-and-hour pillar readings.