We spend plenty of time talking about automatic movements, power reserves, and the like, but spring drive watches are worthy of attention and are extremely interesting to talk about. They have been a part of the Grand Seiko and Seiko catalogs for almost two decades, first in limited edition before becoming more mainstream.
Spring drive movements use some components from automatic movements, including a mainspring and barrel, but the escapement and balance wheel from automatics are replaced. Seiko uses proprietary designs for its regulator system and unique rotor, while quartz crystal and an integrated circuit regulate the speed of the rotor. The movement’s signature sweeping seconds hand comes from its direct connection to the rotor instead of relying on the rhythmic mechanical movements in automatics.
Beyond the mesmerizing sweep of their seconds hand, watches with spring drive movements get long power reserves, with up to 72 hours in some cases. Seiko uses a special in-house-developed alloy that it promises is highly temperature and corrosion-resistant. The company’s unique winding mechanism provides more power with fewer turns of the crown or rotations of the rotor. Spring drive watches are also amazingly accurate. Seiko claims an accuracy of +/- one second per day, which bests even Rolex at +/- two seconds per day.
Seiko and Grand Seiko offer several watches powered by spring drive movements today, and their catalog goes way beyond plain three-hand watches. The companies offer spring drive dive watches, chronographs, and GMTs, and that’s in addition to their lines of dress and limited-edition watches.