Spring Drive Yellow Gold / Silver / Bracelet

Spring Drive is Grand Seiko's most original contribution to watchmaking — a movement technology that exists nowhere else in the industry. Invented by Yoshikazu Akahane and developed over 28 years before its 1999 debut, Spring Drive combines a traditional mainspring with an electronic regulator: the mainspring drives the gear train, but instead of a mechanical escapement, a tri-synchro regulator converts the mechanical energy into electrical energy to drive a quartz oscillator that governs the speed of the hands. The result is a perfectly smooth, gliding seconds hand — no tick, no sweep — and accuracy of ±1 second per day, an order of magnitude better than mechanical movements. It is simultaneously mechanical and electronic, and entirely neither.

The Grand Seiko SBGA362 was introduced in 2017, when Grand Seiko became a brand of its own rather than a collection within the larger Seiko family. It features a yellow gold case and matching bracelet. It's Spring Drive claiber 9R15 can be seen through the case back.