Sep 14, 2016
Japan's most complicated clock is a 165-year-old mechanical masterpiece
Also known as the Myriad year clock, the Mannen Jimeishou (万年自鳴鐘) was a universal clock designed by the Japanese genius inventor Hisashige Tanaka, who built most of the clock by himself using simple tools like files and saws between the years 1848 and 1851. It is designated as an Important Cultural Asset by the Japanese government.
Standing 63cm high and weighing 38kg, the clock is a true mechanical marvel made of over 1,000 parts and capable of running for an entire year when fully wound. It has six sides, each showing different aspects of time simultaneously. The first one is a wadokei that tells traditional Japanese time where the hours varied according to the seasons (for example, longer daylight hours in summer and shorter in winter). The second one shows the 24 seasonal periods of the traditional Japanese solar year. The third side shows the day of the week, while the fourth indicates the date according to the Chinese sexagenary cycle (translation: it shows the day based on the ten lunar calendar signs and the twelve signs of the Chinese zodiac). The fifth side displays the day of the month and has a sphere in the center that shows the phases of the moon. Finally, the last dial shows the usual time.
Placed above the six faces is a glass dome containing a plate depicting the island of Japan and two small globes showing real-time position of the Sun and Moon relative to the Earth. All without any microchips!
In 2004, Japanese government funded a project with a goal of making a replica of the clock to be shown at the Expo 2005. This was an overwhelming task — it took over 100 engineers a year to produce the copy, but even with all the technology available today, it wasn’t possible to produce exact copies of certain parts such as the brass metal plate for the mainsprings, which they substituted with steel. This was the first time the clock was disassembled. Microscopes were used to study all the different components and gears.
Hisashige Tanaka was one of the most important inventors of his time, and just a few years before his death in 1881, he established Japan’s first telegraph manufacturing company Tanaka Seisakusho. Later the company was renamed to Shibaura Seisakusho, and after a merger with the electric company Tokyo Denki in 1939, the company became Tokyo Shibaura Denki, better known today as Toshiba.
In Tanaka’s birthplace, the city of Kurume in Fukuoka Prefecture, in front of the Kurume Station, there’s a big mechanical clock with depictions of Tanaka’s inventions. The clock was designed to look like the actual taiko drum clock that he himself made. At given times, the clock turns around and a Giemon doll comes out to explain some of Hisashige’s works through gestures.
Today, the original Myriad year clock is owned by Toshiba Corporation and is permanently displayed at the National Museum of Nature and Science in Tokyo. The replica can be seen at the Toshiba Science Museum in Kawasaki.