Grand Seiko 9R Spring Drive

Spring Drive is Seiko’s exclusive movement that achieves an unprecedented level of accuracy (+/- 15 seconds per month on average, equivalent to +/- 1 second per day) by regulating a spring-driven watch with state-of-the-art electronic technology that functions without batteries or other external power source.

One of its unique features is a true continuously sweeping second hand, instead of the traditional beats per time unit as seen with traditional mechanical and most quartz watches. (Wikipedia)

Grand Seiko 9R Spring Drive uses a mainspring, barrel, automatic winder and stem winding like in a mechanical watch to store the watch energy. The conventional escapement is replaced with a device that Seiko calls a Tri-synchro Regulator to regulate the unwinding of the mainspring. The regulator controls the use of the three forms of energy used in the Spring Drive mechanism; the mechanical power of the mainspring, the electrical energy generated from this mechanical power, and the electromagnetic energy that governs the rotation of the glide wheel.

As one of the very few fully integrated watch manufactures in the world, Grand Seiko possesses a mastery over the full breadth of the watchmaking process from the research and development of component materials to manufacture, assembly, adjustment, inspection and shipment.

Grand Seiko defines the essence of watchmaking in the elements of precision, beauty, legibility, durability and ease-of-use. As a world-leading watch manufacture, it embodies that very essence in the unrivaled quality in every watch presented to the world.

— The Shinshu Watch Studio drives innovative ideas and novel technologies behind the ultimate quartz watches and Seiko’s exclusive Spring Drive watches.

Each of these pre-eminent watch studios plays a pivotal role in combining the cutting-edge technology and masterful craftsmanship necessary to reach the pinnacle of quality.