The Seiko Spring Drive watch movement technology is a unique and efficient system that makes it possible to create a watch movement with high accuracy.
The Seiko's Spring Drive is unique because this automatic watch requires no external power source. Until now, it is the only watch movement in the world with a regulator (located on its mainspring) without an escapement and is a combination of mechanical and electronic technology. According to Seiko watches, The spring dive has "one-second-a-day" accuracy.
What is a spring dive?
The spring drive system is a 21st-century watchmaking innovation. It's the epitome of an electromechanical system, combining the best of both worlds. In a conventional mechanical watch, a mainspring is wound to store energy as potential energy. But in a spring drive watch, this potential energy is converted into kinetic energy by an electronic motor rather than by a mechanical rotor.
How does spring drive work?
An "escapement" is used to control the unwinding of the spring. The escapement is another mass-spring system that exchanges kinetic and potential energy to regulate the motion of the mainspring. When the spring is released, it converts the gears' potential energy into kinetic energy. The problem with this system is that it is susceptible to shock, temperature, positioning, and external or other magnetic forces, which can adversely affect timekeeping accuracy.
This is where the spring drive appears. Instead of using an escapement, you have an electromagnetic-mechanical system called the "Trip-Snycro regulator (TSR)".
The rotation of a watch's mainspring generates a tiny electrical current through electromagnetic induction (EMI). This drives an IC to vibrate a quartz crystal. The integrated circuit drives a quartz crystal to vibrate. The integrated circuit then compares the quartz's vibrations to the balance wheel's rotation rate to regulate how fast it releases its energy. That is, with the help of the electromagnetic force on the balance wheel.
What is so special about the spring drive?
The truly appealing beauty of the spring drive is that no batteries or capacitors are required, as all of the watch's energy comes from its mechanical spring potential energy. The quartz is used as a brake to regulate the watch's speed.
Who invented the spring drive?
In 1977, Suwa Seikosha (now a part of Seiko Epson) engineer Yoshikazu Akahane conceived the idea of using a mainspring to power a quartz timing package. He called it Spring Drive.
"If you coast down from the top of a mountain by bicycle beside a pacemaker, the force of gravity provides all the energy you need. You may even have to brake periodically so as not to overtake the pacemaker."
-Yoshikazu Akahane
In 1983, Akahane and his team began work on the first Spring Drive prototype. Although existing integrated circuit technology limitations prevented them from achieving a 48-hour run time, the prototype proved that Akahane's theory was more than just theoretical.
1982 prototype  | 1993 prototype  |
Which Seiko watch collection have spring drive?
In 1999, Seiko released its Spring Drive movement in watches distributed by its Credor, Presage, Prospex, and Grand Seiko brands.
Seiko Credor
Credor is a luxury brand of watches that Seiko has created to appeal to the Japanese market. Credor comes from the French phrase Créte d'Or, which translates to 'crest of gold' and represents the ultimate of luxury. Credor is intended to be an alternative to other European dress watches, focusing on classic styling cues. Many Credor watches lack the Seiko name and have exclusive complications, such as hand-carved components and skeletonised dials.
Grand Seiko
Grand Seiko watches were created in the 1960s to achieve perfection. The designers and engineers behind this brand have always strived for world-leading durability, accuracy, and charm standards. The Grand Seiko collection offers not only revolutionary spring drive movements that are accurate within a second per day but also traditional mechanical movements that meet stricter standards than those required for chronometer status.
Seiko Presage
Seiko's Presage collection offers appealing options for every budget and style, from the higher-end Masterpiece models to the more affordable dress watch timepieces. The Presage collection draws its design inspiration from Seiko's most important historical watch, the 1964 Crown Chronograph. This watch was Japan's first chronograph to feature calibre 5719 movements. It kickstarted Seiko's journey in chronograph watchmaking and led to the manufacturer presenting its first automatic chronograph in 1969.
Seiko Prospex
As stated on the Seiko official website, the Prospex timepieces collection is made for sports lovers and adventure seekers who challenge limits in sky, water, or land. Seiko Prospex watches are a favourite of avid adventurers, explorers and divers. The Prospex line collection is known for its robust designs, accuracy, and unique craftsmanship. The chronometers Prospex watches have developed a reputation for their trusted performance.
List of Seiko spring drive calibre movements
Caliber 9R65 (30 jewels)  Power reserve: 72 hr | Caliber 9R66 (30 jewels)  Power reserve: 72 hr | Caliber 9R86 (50 jewels)  Power reserve: 72 hr |
Caliber 9R15 (30 jewels)  Power reserve: 72 hr | Caliber 9R84 (41 jewels)  Power reserve: 72 hours | Caliber 9R96 (50 jewels)  Power reserve: 72 hr |
Caliber 9R16 (30 jewels)  Power reserve: 72 hours | Caliber 9R01 (56 jewels)  Power reserve: 192 hours | Caliber 9R02 (39 jewels)  Power reserve: 84 hours |
Caliber 9R31 (30 jewels)  Power reserve: 72 hours | Caliber 9RA5 (38 jewels)  Power reserve: 120 hours | Caliber 9RA2 (38 jewels)  Power reserve: 120 hours |