Ke (unit)

The ke (Chinese: 刻; pinyin: kè) is a time unit in traditional China. The ke is the extension of the scale^[1] on the sundial or the rule of the water clock.^[2] In French decimal time, ke is equivalent to 10 decimal minutes, sometimes called a décime.
The major ke is 14.4 minutes (14 minutes 24 seconds), which is the time between two centiday scales, and the minor ke is 2.4 minutes (2 minutes 24 seconds),^[3] which is the common factor time between centiday scale and shi scale. It was customary to subdivide the minor ke into 10 fen (Chinese: 分; pinyin: fēn), just as cun and mace; thus the major ke is divided into 60 fen.

There were various attempts to redefine a day to 96, 108, or 120 ke, in order to abolish the minor ke. During the Qing dynasty around the time of the arrival of Jesuit missionaries, the ke was finally redefined to ¹⁄₉₆ day, or ¹⁄₈ shi, or a quarter of an hour. And fen is currently used to refer to ¹⁄₆₀ of an hour, or 1 minute.

See also

• Chinese calendar
• Decimal time

Notes

1. F. Richard Stephenson and David A. Green; Historical supernovae and their remnants, Oxford University Press, Oxford (2002), pages 15-16. ISBN 0-19-850766-6
2. According to the Shuowen Jiezi from Xu Shen, “漏以铜壶盛水，刻节，昼夜百刻。” Translation: “The water clock holds the water in the copper pot, and marks the scale on the rule. there're 100 scales which represents a day.”
3. 600 is the LCM of 100 and 24, so the time between centiday and shi scale may be ¹⁄₆, ¹⁄₃, ¹⁄₂, ²⁄₃, or ⁵⁄₆ major ke. The ¹⁄₆ major ke is the common factor

References

• Ronan, Colin p 247-250 in Walker, Ch. ed.: Astronomy before the telescope. Brit. Museum P., UK (1999). ISBN 0-7141-2733-7