To provide a clocking device which can easily confirm isochronic.
In an electronic control type mechanical timepiece 1, light emission frequency H2 of light which is irradiated, rotational frequency H1 of an inertial plate 40, and the number M of arms 43 of the inertial plate 40 are made to satisfy a relevant expression described in the text. Thus, the light emission frequency H2 is synchronized with the rotational frequency H1 of the inertial plate 40. Accordingly, an afterimage phenomenon of the arms 43 provided to the inertial plate 40 is generated, and the arms 43 can be made to appear approximately stationary, despite the rotation of the inertial plate 40. In a state in which the electronic control type mechanical timepiece 1 is turned over under a fluorescent lamp, when the arms 43 of the inertial plate 40 appear to be stationary, the inertial plate 40, as well as a rotor 31, are rotated at the prescribed frequency H1 in synchronism with the light emission frequency H2, while properly maintaining isochronic. Thus, the user of the electronic control type mechanical timepiece 1 can easily confirm the isochronic.
Kanji Nakayama
Tsuyoshi Ishizaki
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