Hisashige Tanaka was the founder of the company that would become the root of Toshiba, and was an engineer who was active from the late Edo period to the Meiji era.
Hisashige Tanaka studied astronomy, Onmyōdō (Japanese esoteric cosmology), and calendrical science, and combined this knowledge to create a multi-functional astronomical clock called the "Man-nen jimei-shouaa(Man-nen dokei)."
The six-sided display and celestial sphere work in conjunction to visualize the flow of time, such as seasons and time of day, as caused by the movements of the Earth, Moon, and Sun. Furthermore, once wound, it operates continuously for one year.
The Perpetual Clock has undergone several restorations and is currently on display at the National Museum of Nature and Science.
In preparation for the 2005 Aichi Expo, a national project was implemented to disassemble and investigate the Perpetual Clock and create a replica using current technology for display.
Because it had been stored in a non-functioning state for some time, its original operation was not fully understood, but during this investigation and restoration process, the complex and intricate mechanism of the first-sided split-gear type Japanese clock was revealed.
I got so fascinated that I made an Apple Watch app based on it
It shows:
* traditional Japanese time
* sun / moon movement
* moon phase
* zodiac hour names
* seasonal hour changes
* star map
Wadokei57 was inspired by the 万年時計[まんねんどけい]（man-nen-dokei), an astronomical clock created by Hisashige Tanaka, the founder of Toshiba.
TOSHIBA
https://toshiba-mirai-kagakukan.jp/en/history/toshiba_history/hisashige.htm
Free beta version Wadokei57
https://testflight.apple.com/join/3vyH6nEG
App Store Wadokei57
https://apps.apple.com/us/app/wadokei57-astronomical-watch/id6748839654