Seiko’s Spring Drive
What: This caliber boasts a unique combination of mechanical and quartz parts – think of it as a mechanical watch with electronic precision. It has a mainspring that transfers energy to a tri-synchro regulator that converts it into electrical pulses, resulting in a superlative precision of +/- one second per day.
Also see: 10 watches, including Seiko Astron, that changed the world of watchmaking
What’s new: With the Spring Drive celebrating its 20th anniversary this year, Seiko has upgraded the movement into the manual-winding Caliber 9R02 with a power reserve of 84 hours, an increase from the regular 72 hours.
This is made possible with two mainsprings, placed parallel to each other in a barrel, and a Torque Return System that translates 30% of unused energy to rewind the mainsprings.
The barrel, which is visible on the caseback, is shaped like a bellflower, the symbol of Shiojiri, the city where Seiko’s Micro Artist Studio that makes Caliber 9R02 is located. The power reserve indicator can be found next to it.
