To convert ancient Chinese time, first identify the system, not just the word. A shichen is usually mapped to two modern hours; a ke may be a mark in a 100-part day or, in a later 96-ke system, a 15-minute quarter; a geng is a night watch whose length can depend on context; and dian may count beats or subdivisions within a watch.
In brief: Use the 12-shichen table confidently as a modern reference. Treat ke, geng, and dian as context-dependent until you know the period, instrument, and setting. A historical novel, court record, water-clock scale, and maritime manual may not be using the same conversion.
Contents
- Quick conversion table
- Shi and shichen
- Ke: a mark that changed length
- Geng and dian at night
- A four-step conversion method
- Worked examples
- Frequently asked questions
Quick conversion table
| Term | Chinese | Safest modern starting point | Main warning |
|---|---|---|---|
| Shi / shichen | 时 / 时辰 | One of 12 periods; about 2 hours | Boundaries and reckoning can vary by source |
| Ke | 刻 | 1/100 day = 14.4 minutes in a 100-ke system; 15 minutes in a 96-ke system | Do not assume every dynasty used the same day division |
| Geng | 更 | A watch, usually part of the night | Night length, urban practice, and maritime usage differ |
| Dian | 点 | A beat or subdivision associated with watch reporting | Not a universal modern-minute value |
This table is a decision aid, not a universal conversion engine. Scholarship on ancient Chinese time laws explicitly notes that several systems coexisted and that subdivision rules were not uniform (Mechanism and Machine Theory).
Shi and shichen
For general reading, use the standard 12-period table:
| Branch time | Modern range | Branch time | Modern range |
|---|---|---|---|
| Zi | 11 p.m.–1 a.m. | Wu | 11 a.m.–1 p.m. |
| Chou | 1–3 a.m. | Wei | 1–3 p.m. |
| Yin | 3–5 a.m. | Shen | 3–5 p.m. |
| Mao | 5–7 a.m. | You | 5–7 p.m. |
| Chen | 7–9 a.m. | Xu | 7–9 p.m. |
| Si | 9–11 a.m. | Hai | 9–11 p.m. |
The Hong Kong Observatory publishes this mapping as the relationship between the 12 shichen and the present time system (HKO).
“Hour” is a convenient translation, but “double-hour” prevents a common error. If a story says an event took one shi, a modern reader should initially imagine roughly two hours—not 60 minutes—unless the text or translator defines a different usage.
Ke: a mark that changed length
Ke (刻) means a cut, engraving, or mark. In timekeeping, it was associated with marks on a scale, including the indicator of a water clock.
One influential system divided the entire day into 100 ke:
24 hours × 60 minutes = 1,440 minutes
1,440 ÷ 100 = 14.4 minutes per keThat arithmetic is exact for a 100-ke day. It is not proof that every reference to ke means 14 minutes 24 seconds. Historical systems also used other totals. A later 96-ke day makes each ke 15 modern minutes, which aligns with the modern Mandarin use of yike for a quarter hour.
The key reading question is therefore: Which time law is this source using? If the source does not say, an approximate translation such as “a mark later” may be more honest than a precise minute.
Geng and dian at night
Geng (更) is commonly translated as a night watch. The familiar late-imperial model divides the night into five watches, announced through patterned sounds. But night is not the same length throughout the year.
The Palace Museum describes a Qing watch clock with mechanisms for starting, ending, and adjusting the watches according to night length across the 24 solar terms (Palace Museum). That object is direct evidence that “one watch always equals exactly two hours” is too simple for every historical context.
Dian (点) can refer to counted beats or smaller positions within watch reporting. A phrase such as “third watch, second beat” belongs to a reporting system, not automatically to one permanent modern timestamp. To convert it, you need the local rule for that source.
Maritime texts add another complication. A recent study of Chinese sailing manuals notes routes expressed as a compass direction for a number of geng, with 10 geng equaling 24 hours in that navigational context (Journal of Chinese History). That sea-watch unit should not be silently substituted for an urban night watch.
A four-step conversion method
Step 1: Identify the genre
Is the source a poem, novel, legal record, court diary, astronomical manual, temple schedule, or sailing guide? Genre tells you how much precision the writer probably intended.
Step 2: Identify the period and place
Time laws, calendars, institutions, and local reporting practices changed. “Ancient China” is too broad to choose a fine-grained conversion.
Step 3: Identify the measuring system
Look for clues:
- an Earthly Branch suggests shichen;
- a water-clock scale suggests ke;
- drums, gongs, or patrols suggest watches;
- a compass course and voyage duration suggest maritime geng.
Step 4: Match the precision of the evidence
Use a range when the source gives a period. Use an exact minute only when the historical convention and starting point justify it. Preserve uncertainty near boundaries.
Worked examples
“At Mao hour”
Start with 5:00–7:00 a.m. in the standard modern mapping. In literary prose, “around dawn” may communicate the scene more naturally.
“After three ke” in a 100-ke system
Three ke equal 43.2 modern minutes. Round only if the purpose allows it, and state that the calculation assumes 100 ke per day.
“At the third watch”
Do not immediately write “midnight.” Determine whether the source uses five seasonal watches, fixed equal watches, or a literary convention. “During the third watch” may be the responsible first translation.
“Sail for two geng”
If a maritime manual explicitly uses the 10-geng day described in the navigation study, two geng correspond to 4.8 hours. That conversion belongs to that navigational system.
Frequently asked questions
How many minutes were in one ke?
In a 100-ke day, one ke is 14.4 modern minutes. In a 96-ke day, it is 15 minutes. Other historical subdivisions existed, so identify the source’s system before choosing.
How long was one shichen?
Approximately two modern hours in the standard 12-part conversion. Read The 12 Shichen for the full chart.
Was one geng always two hours?
No. Five-watch night systems could respond to seasonal night length, while maritime manuals could use geng in a different ten-per-day voyage calculation.
What is “third watch” in modern time?
It is often associated with the middle of the night, but an exact conversion depends on the watch system, season, and source. Avoid false minute-level precision.
What does dian mean after geng?
It generally indicates a counted beat or subdivision in watch reporting. Its exact timing depends on the reporting convention in use.
Convert the system before converting the number
Ancient Chinese time becomes much clearer when shi, ke, geng, and dian are treated as parts of specific systems. Begin with the genre and period, identify the measuring rule, and then convert only as precisely as the evidence allows. For the environmental names paired with the 12 shichen, continue with Twelve Traditional Chinese Times of Day.