Japan · Conceived 1977; released 1999
Spring Drive
Partially verifiedA new kind of watch regulation between mechanical and quartz: spring-powered, with no battery, but regulated electronically to about a second a day.
Spring Drive, conceived by Yoshikazu Akahane in 1977 and released in 1999, keeps the mainspring and gear train of a mechanical watch but regulates them against a quartz signal instead of a balance and escapement.
Background
The Spring Drive concept was first conceived in 1977 by Yoshikazu Akahane at Suwa Seikosha to create a watch movement regulated by a quartz signal while maintaining a mechanical gear train. Development faced significant technical hurdles related to the energy consumption of the reference quartz crystal and integrated circuit, which initially made achieving a 48-hour power reserve impossible. Success was finally achieved during a third attempt in 1997, which utilized components with approximately one hundredth of the energy consumption of the initial 1982 design.
The system replaces the traditional balance wheel and escapement with a Tri-synchro Regulator, a phase-locked loop that governs the rotational speed of a glide wheel using an electromagnetic brake. This mechanism results in a true continuous sweep of the seconds hand, as the glide wheel regulates the power delivered from the barrel to the hands.
Written from the encyclopedia entries listed under Sources; each statement was checked against the cited text.
How it works
- The Tri-synchro Regulator samples the rotational speed of the glide wheel once every rotation to adjust the applied electromagnetic braking force.
- Energy is stored using a conventional mainspring and barrel, supplemented by either stem or automatic winding systems.
Later history
- Patents for the invention were first applied for in 1982, with over 230 total patents subsequently filed worldwide.
- Following a public announcement in 1997 and a presentation at the 1998 Basel Watch Fair, the first commercial production models were released in Japan in December 1999.
- The Micro Artist Studio, established in 2000, produces advanced calibers for the brand, including complicated models like the Sonnerie and Minute Repeater.
Impact on watchmaking
- Seiko — Spring Drive movements are made for Seiko's brands, including Grand Seiko and Credor.
How to verify this yourself
Check the cited museum record or maker's archive first; for patented work, confirm the number and date from the specification itself (Espacenet covers most European, US and Japanese patents) rather than from secondary retellings.
Manufacturers known to have used it
- Seiko (Grand Seiko, Credor, Presage, Prospex)
Related photographs
No confidently matched photograph of this subject has been found yet. These photographs show a closely related record, and are not examples of the type described on this page.
Sources & references
- Spring Drive, Wikipedia (English), retrieved 2026-11-02 (text CC BY-SA 4.0)
- Wikipedia, Spring Drive (revision cited below)
Where sources disagree, the disagreement is stated rather than resolved silently.