Myriad year clock

A myriad year clock is a chronometer designed by Hisashige Tanaka sometime between 1850 and 1851. It keeps its motion for longer than 200 days after one full winding. The device is 53 cm in height, 26 cm in width and it has six dials. Two streams are integrated in the highest level in it: One is the latest Western mechanism and the other is the traditional technique and skill in Japanese clock (wa-dokei) technology. The six dial faces correspond to many time and calendar systems: Japanese, Eastern and Western. It automatically adapts to the old Japanese temporal hour system by a devised mechanism. In this system, the unit of time, say one hour in the present standard system, is different in daytime and night, and summer and einter. The time from sunrise to sunset and the time from sunset to sunrise were each divided by six in Japan.

A replica of this timepiece can be seen at the Aichi Expo in Japan or in Japan's National History Museum.