Lòukè jīng 漏刻經
Manual of the Clepsydra by 朱史 (Zhū Shǐ, Shèrén 舍人 under Chen Wéndì, fl. 560–566, zhuàn 撰; attribution tentative — see Abstract) — source file marks author as 闕名 (anonymous)
About the work
A short Liáng-period (or possibly later-Six-Dynasties anonymous) technical-and-practical manual for the construction and operation of a small floating-bowl clepsydra (lòukè 漏刻 — literally “leak-and-scale,” the standard Chinese water-clock from the Hàn through the Sòng). The work is unusual for its survival as a freestanding jīng 經 (“manual”) — most pre-Táng clepsydra material is preserved only in fragments quoted in the lǜlì zhì 律曆志 sections of the dynastic histories. Endymion Wilkinson’s Chinese History: A New Manual (§28.4.3, on the meaning of jīng in pre-Hàn through Táng titles) lists the Lòukè jīng explicitly as one of the technical jīng — “treatises and manuals such as XuánNǚ zhànjīng 玄女戰經 (Xuan-Nü’s manual of warfare) or Lòukè jīng 漏刻經 (Clepsydra manual)” — noting that the rendering “classic of” for such works is to be avoided in favour of “manual of.”
The Kanripo title attribution to Zhū Shǐ 朱史 follows the krp-titles register (@CH2d1669); the source file itself marks the author as 闕名 (“name omitted”), and no internal evidence of authorship survives. See 朱史 for the attribution status.
Abstract
Composition window: the broad range notBefore 560 / notAfter 1300 reflects two compounded uncertainties. First, the Kanripo register’s “Liáng” dynastic placement (502–557) for the author conflicts with the Suí shū lǜlì zhì 隋書·律曆志 (juàn 17, Lòukè 漏刻 section), which secures Zhū Shǐ 朱史 as a Shèrén 舍人 of the Chen 陳 (not Liáng) dynasty, commissioned during the Tiānjiā 天嘉 era (560–566) of Wéndì 文帝 to construct the imperial clepsydra following the orthodox 100-kè 刻 division (the same 100-kè day-and-night system that the surviving Lòukè jīng text adopts, “yī rì yī yè tōng jì yībǎi kè” 一日一夜通計一百刻). The principal Liáng-period Lòu jīng 漏經 cited in the Suí shū was by Zǔ Gēng 祖暅 (祖沖之 Zǔ Chōngzhī’s son), not by Zhū Shǐ. The Kanripo “Liáng” attribution is therefore most likely a conflation. The dynastic field is here corrected to 陳, following the Suí shū witness, with the krp-titles “Liáng” reading flagged.
Second, the surviving text itself cannot be a 6th-century document: it explicitly uses Tàipíng qián 太平錢 as standard counterweights (§§3–4 below), but the Tàipíng tōngbǎo 太平通寶 was first minted in the Sòng TàipíngXīngguó 太平興國 era (976–984); §1 also names cí yú 磁盂 (porcelain bowls) as substitute for the brass tóng yú, more characteristic of Sòng-period domestic technology. The surviving manual is thus best understood as a Sòng or post-Sòng popular clepsydra manual conventionally attributed to Zhū Shǐ — perhaps because Zhū Shǐ’s historically documented 100-kè clepsydra-system is also the surviving text’s underlying time-division. The Kanripo file’s internal 闕名 (anonymous) marking is more textually accurate than the register’s Zhū Shǐ attribution.
The text opens with a programmatic preface arguing that the standard pre-existing methods of clepsydra-construction in the author’s day have departed from the ancient norm: each artisan “[asserts] his own blind technique” (gè sì gǔ shù 各肆瞽術), so that the resulting instruments have no consistent regulation (zhìdù jì wú zé 制度既無則) and the time-readings differ by amounts greater than the seasonal correction can account for. The author proposes a new compact design — a “looped-drip” mechanism (dīlòu xúnhuán zhī fǎ 滴漏循環之法) — that is simple, durable, and portable (“suī chū wǔlǐ zhī wài, qièsì jiē kě fù xíng yú fánàn zhī yú” 雖出五里之外，篋笥皆可附行于凡案之隅 — “even when one travels more than five lǐ away, the [device] in a chest can be carried along and set down at the corner of any table”).
The technical content is then organised in five short sections:
(1) 造盂法 Zào yú fǎ (“Method for the [Water-]bowls”): the device uses two bronze bowls, one large and one small. The large bowl holds the water, with no fixed dimension provided beyond that it be larger than the small bowl. The small bowl is more rigidly specified: weight, five [units, illegible in source]; height 3 cùn 4 fēn; rim-and-base diameter both 4 cùn 7 fēn; cylindrical (sides straight up-and-down); calibrated by weight against fifty Tàipíng 太平 cash for consistency. After fabrication, a small needle-eye perforation is drilled at the base of the small bowl, which then floats upside-down on the water-surface of the large bowl. Water flows upward through the perforation into the small bowl (driven by the pressure of the large bowl’s water against the air-filled interior of the inverted small bowl), and time is read off by a graduated stick chóu 籌 inserted into the small bowl: when the water reaches the zǐ mark, it is the zǐ hour; when it reaches wǔ, the wǔ hour; and so on.
(2) 下漏法 Xià lòu fǎ (“Method for Operating the Leak”): at sunrise each day, the small bowl is set floating upright on the large basin’s water-surface; by sunset, water has leaked into it and it has sunk. The contents are then emptied and the bowl re-floated for the night-shift; the cycle is completed at the next sunrise. The day-and-night cycle is determined by the timing of the bowl’s submersion at the two transition points. The author emphasises that the water must be filtered clean before re-use to prevent the needle-hole from clogging.
(3) 造籌法 Zào chóu fǎ (“Method for the Graduation-Stick”): the chóu is made from thin bamboo and graduated into twelve segments, each 2 fēn 5 lí in length, totalling 34 fēn. At the four yínshēnsìhài 寅申巳亥 quarters, an additional 4 fēn is added (the wéi piān tiān zhī shù 維偏添之數, the “additional measure for the cardinal-inclines”). Cash are also distributed across the floating-bowl as ballast to fine-tune the rate (twelve months, twelve cash allocations).
(4) 加減法 Jiā jiǎn fǎ (“Adjustment Method”): a month-by-month seasonal correction table for the day/night ballast distribution. At the eleventh-month node (shíyī yuè jié 十一月節 — winter solstice), 20 Tàipíng cash are placed in the small bowl during the day, none at night. The night ballast is incremented and the day ballast decremented by one cash every seven days; the proportions reverse at the fifth month (summer solstice), with 0 cash by day and 20 by night. Equal allocations (10/10) occur at the spring (二月) and autumn (八月) equinoxes.
(5) 推二十四 / 定太陽出沒法 / 約十二時 Tuī èrshísì / Dìng tàiyáng chūmò fǎ / Yuē shíèr shí (“Reckoning the 24 Solar Terms / Determining Sun-rise and Sun-set / The Twelve Watches”): three short mnemonic verses giving the standard 24 solar terms by month, the sun-rise / sun-set directional reading by month, and the popular names of the 12 shíchen (“bànyè zǐ, jīmíng chǒu, píngdàn yín, rìchū mǎo, shíshí chén, yúzhōng sì, rìzhōng wǔ, rìdié wèi, būshí shēn, rìrù yǒu, huánghūn xū, miándìng hài” 半夜子，鷄鳴丑，平旦寅，日出卯，食時辰，禺中巳，日中午，日晐未，晡時申，日入酉，黃昏戌，眠定亥 — “midnight is zǐ, cockcrow is chǒu, dawn is yín, sun-up is mǎo, mealtime is chén, mid-morning is sì, sun-noon is wǔ, sun-declination is wèi, late-afternoon is shēn, sun-down is yǒu, twilight is xū, sleep-fixing is hài”).
The work is unusual in the Chinese clepsydra tradition for its emphasis on a small-scale, portable, household clepsydra rather than the monumental state-clock of the lǜlì zhì tradition. The Liáng-period dating (or anonymous Six-Dynasties dating) is compatible with the period in which household-and-monastic timekeeping technology became widespread alongside the rise of Buddhist monastic horology — the cháozhōng 朝鐘 (“morning bell”) and Buddhist liturgical schedules of the Liáng-period imperial Buddhist court documented in the Liáng shū and the Gāosēng zhuàn 高僧傳 would have required such portable timepieces.
Translations and research
- Needham, Joseph, Wang Ling, and Derek J. de Solla Price. Heavenly Clockwork: The Great Astronomical Clocks of Medieval China. Cambridge University Press, 1960, ch. 2 — surveys the pre-Sòng clepsydra tradition with extensive citation of Lòu-kè jīng and related manuals; principal English-language reference.
- Needham, Joseph. Science and Civilisation in China, vol. 3 (1959), pp. 313–329 — the lòu-kè tradition in pre-Táng China.
- Hua Tongxu 華同旭. Zhōngguó lòu-kè 中國漏刻. Hefei: Ānhuī kē-xué jì-shù chū-bǎn-shè, 1991 — the standard modern Chinese monograph on the history of Chinese water-clocks.
- Wilkinson, Endymion. Chinese History: A New Manual, 6th edn., 2022, §28.4.3 (on the genre of technical jīng including Lòu-kè jīng) and §A (chronology / time-measurement).
Other points of interest
The upward-leak mechanism described in §1 of the manual is technically remarkable: rather than the standard out-flow clepsydra (in which water drips out of a higher reservoir into a graduated lower reservoir) or the in-flow clepsydra (water drips from a higher reservoir into a graduated receiving bowl with a calibrated float), the Lòukè jīng’s small inverted bowl floats on the larger basin, and water rises up through the basal needle-hole into the small bowl by pneumatic pressure as the air inside the small bowl gradually escapes. This is an early Chinese instance of explicit pneumatic reasoning in clock-construction, and represents a distinct mechanical principle from the standard HànWèiJìn out-flow / in-flow clepsydras. The principle is documented in later Chinese horological practice as the fújiàn 浮箭 (“floating-arrow”) clepsydra and reappears in Buddhist monastic timekeeping; the Lòukè jīng’s description is one of the earliest extant detailed accounts.
The source-file at line 42 includes a minor textual oddity: “zhìdù jì wú&-;zé” 制度既無&-;則 — the &-; (a backslash-dash-semicolon sequence) is a OCR-or-transcription artefact for an illegible character, probably yǒu 有 or similar. Preserved here as a textual slip in the source.