A wadokei is a mechanical clock that has been made to tell traditional Japanese time, a system in which daytime and nighttime are always divided into six periods whose lengths consequently change with the season. Mechanical clocks were introduced into Japan by Jesuit missionary (in the 16th century) or Dejima (in the 17th century). These clocks were of the lantern clock design, typically made of brass or iron, and used the relatively primitive verge and foliot escapement. Tokugawa Ieyasu owned a lantern clock of European manufacture.
Neither the pendulum nor the balance spring were in use among European clocks of the period, and as such they were not included among the technologies available to the Japanese clockmakers at the start of the sakoku in Japanese history, which began in 1641. The isolationist period meant that Japanese clockmakers would have to find their own way without significant further inputs from Western developments in clockmaking. Nevertheless, the Japanese clockmakers showed considerable ingenuity in adapting the European mechanical clock technology to the needs of traditional Japanese timekeeping.
Christian missionaries were among the first to introduce Japan to Western mechanical spring driven clocks. Francis Xavier, a Spanish Society of Jesus saint and missionary, gave Ouchi Yoshitaka, a daimyō of the Sengoku period, a mechanical clock in 1551.Yokota, Yasuhiro. "A Historical Overview of Japanese Clocks and Karakuri". International Symposium on History of Machines and Mechanisms (2008), 177. Other missionaries and embassies soon followed, with a mechanized clock being given to Oda Nobunaga in 1569 and Toyotomi Hideyoshi in 1571 by Papal envoys, and two clocks given to Tokugawa Ieyasu, one in 1606 by a missionary and one in 1611 by a Portuguese envoy. The oldest surviving western clock in Japan dates back to 1612; it was given to Shōgun Ieyasu by the viceroy of Mexico (then New Spain).
Near the turn of the 17th century, the first Western-styled, mechanical clocks were produced by Japanese natives. Tsuda Sukezaemon is reported to have made a mechanical clock in 1598 after he had examined and repaired many imported clocks on his own. Japanese clock making was facilitated in the 17th century by missionaries living in Japan. Christian missionaries were the first to instruct the Japanese on clockmaking in the Amakusa around the turn of the 17th century. "History of the Japanese Horological Industry." History of the Japanese Horological Industry. N.p., n.d. Web. 02 April 2013. Section 1.
The Edo period (1603–1868) saw the adaptation of Western techniques to form a unique method of clock making in Japan. A double escapement was designed by Japanese clockmakers in order to develop a clock that followed the uneven, traditional Japanese time schedule.Pacey, Arnold. Technology in World Civilization: A Thousand-year History. Cambridge, MA: MIT, 1990. Page 88. These clocks, called wadokei, were built with different methods in order to follow the temporal hour system ( futei jiho 不定時法). The foliots of the clocks have several divisions allowing the user to set a relatively accurate rate.Fernandez, M. P., and P. C. Fernandez. 1996. "Precision Timekeepers of Tokugawa Japan and the Evolution of the Japanese Domestic Clock". Technology and Culture. 37 (2), 223. Foliot-controlled clocks, despite being widely replaced in Europe by circular-balanced clocks, were utilized in Japan due to their adaptability to the temporal hour system.Fernandez, M. P., and P. C. Fernandez. 1996. "Precision Timekeepers of Tokugawa Japan and the Evolution of the Japanese Domestic Clock". TECHNOLOGY AND CULTURE. 37 (2), 224. Constant weight and dial adjustments led Japanese clock makers to develop the nichō-tenpu tokei or "two-bar governor clock", around 1780.Yokota, Yasuhiro. "A Historical Overview of Japanese Clocks and Karakuri". International Symposium on History of Machines and Mechanisms' (2008), 179. The weights in the nichō-tempu tokei'' were automatically set for the correct time of day or night with the use of two governors or balances, called tenpu.
A key component of the development of Japanese clocks was the publication of Hosokawa Hanzo's Karakuri Zui in 1796, in which he explains production methods of clocks in the first volume, and extra2=or "mechanical dolls" in the second and third volumes. The volume on clockmaking contained highly detailed instructions for the production of a weight-driven, striking clock with a verge escapement controlled by a foliot.Fernandez, M. P., and P. C. Fernandez. 1996. "Precision Timekeepers of Tokugawa Japan and the Evolution of the Japanese Domestic Clock". TECHNOLOGY AND CULTURE. 37 (2), 225. Relatively high literacy rates and an enthusiastic, book-lending society contributed greatly to the work's widespread readership.Yokota, Yasuhiro. "A Historical Overview of Japanese Clocks and Karakuri". International Symposium on History of Machines and Mechanisms (2008), 180.
The production and complexity of clocks reached its peak with Hisashige Tanaka's extra2=or myriad year clock. This has six faces that feature a western clock, a lunar phase indicator, the oriental zodiac, a Japanese temporal clock, the ancient Japanese 24-phase division indicator, and an indicator for the day of the week. "Toshiba : Press Releases 8 March, 2005". Toshiba: Press Releases 8 March 2005. N.p., n.d. Web. 06 Apr. 2013. The clock was said to be able to run for a year on a single winding.
After the Meiji Restoration in 1868, Japan eventually abolished the use of its temporal hour system. The Meiji Cabinet issued Ordinance No. 453 in 1872 which switched Japan from the lunar calendar to the western, solar calendar. "History of the Japanese Horological Industry". History of the Japanese Horological Industry. N.p., n.d. Web. 2 April 2013. Section 3. The switch led to the decline of wadokei and the emergence of a western-styled clock industry in Japan.
As such, Japanese timekeepers varied with the seasons; the daylight hours were longer in summer and shorter in winter, with the opposite at night. European mechanical clocks were, by contrast, set up to tell equal that did not vary with the seasons.
Most Japanese clocks were driven by . However, the Japanese were also aware of, and occasionally made, clocks that ran from springs. Like the western lantern clocks that inspired their design, the weight driven clocks were often held up by specially built tables or shelves that allowed the weights to drop beneath them. Spring driven Japanese clocks were made for portability; the smallest were the size of large , and carried by their owners in inrō pouches.
The typical clock had six numbered hours from nine to four, which counted backwards from noon until midnight; the hour numbers one, two and three were not used in Japan for religious reasons, because these numbers of strokes were used by Buddhism to call to prayer. The count ran backwards because the earliest Japanese artificial timekeepers used the burning of incense to count down the time. Dawn and dusk were therefore both marked as the sixth hour in the Japanese timekeeping system.
In addition to the numbered temporal hours, each hour was assigned a sign from the Japanese zodiac. Starting at dawn, the six daytime hours were:
From dusk, the six nighttime hours were:
The use of clock faces was part of the European technology received in Japan, and a number of arrangements were made to display Japanese hours on clock faces. Some had movable hours around the rim of a 24-hour clock dial. Others had multiple clock faces that could be changed with the seasons. To make a striking clock that told Japanese time, clockmakers used a system that ran two balances, one slow and one fast. The appropriate escapement was changed automatically as the time moved from day to night. The myriad year clock designed in 1850 by Hisashige Tanaka uses this mechanism.
For the temporal hour complication on some of his wrist watches, Masahiro Kikuno uses a series of arms linked to the individual hours. These arms are connected to a single cam with a groove cut in it tuned to the latitude of each watch's individual buyer. The movement of the cam over a single year changes the position of the hours on the watch face.
In 1873 the Japanese government adopted Western style timekeeping practices, including equal hours that do not vary with the seasons, and the Gregorian calendar.
==Gallery==
Temporal hours
Traditional Japanese time system
> sunrise morning 4 noon afternoon 7
> sunset evening 4 midnight before dawn 7
The problem of varying hour lengths
See also
Bibliography
External links
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