Spring Drive

The concept of using a mainspring to power a quartz timing package was first conceived in 1977 by Yoshikazu Akahane (赤羽 好和) at Suwa Seikosha[1] (now a part of Epson after a 1985 merger).

[2] Specified to one second accuracy per day,[3] the movement uses a conventional gear train as in traditional mechanical watches, but rather than an escapement and balance wheel, instead features Seiko's Tri-synchro Regulator system in which power delivery to the watch hands is regulated based on a reference quartz signal.

The Spring Drive uses a conventional mainspring[3] and barrel[4] along with automatic and/or stem winding to store energy, just as in a mechanical watch.

[6] Initial development was hindered by the high energy consumption of the reference quartz crystal and integrated circuit[5] making a watch with a then-target 48-hour power reserve impossible;[7] another attempt in 1993 was also unsuccessful for the same reason.

[1][8] In 1999, the first production models were made available in Japan as limited edition, manual-wind watches in both the Credor and Seiko brands.