What Is the Most Accurate Seiko Movement?
Let’s split this into three categories – mechanical (automatic and hand-winding), quartz, and Spring Drive.
Seiko Mechanical Accuracy
Seiko has a tiered approach to mechanical watch accuracy with their top tier being “AA” which is +5/-3 seconds per day. Only the 9S series of watches fall within this category, so the most accurate Seiko mechanical watch is anything with a movement beginning with 9S (except 9S25 and 9S27). Incidentally these are all Grand Seiko watches, and include automatic as well as hand-winding movements as follows:
Hand-winding: 9S54, 9S63, 9S64
Automatic: 9S51, 9S55, 9S56, 9S61, 9S65, 9S66, 9S67, 9S68, 9S85 (Hi-Beat), 9S86 (Hi-Beat), 9SA5 (Hi-Beat), 9ST1 (Hi-Beat)
Seiko Quartz Accuracy
With quartz watches, the accuracy jumps up as you’d expect. Surprisingly, the most accurate Seiko quartz watches are part of the Superior range from 1978 to around 1983. The best were rated at just ±5 seconds per year! This is thanks to their twin quartz technology, where a second quartz crystal is used to detect and compensate for temperature changes in the main crystal. Seiko released several twin quartz models around that time but these four movements have the highest accuracy:
Seiko Spring Drive Accuracy
Seiko’s Spring Drive, being a kind of hybrid of mechanical and quartz (it’s powered by a mainspring and regulated by a crystal), has accuracy somewhere in between the other two categories. All Spring Drive watches have high accuracy, but the following movements are the most accurate, rated at ±10 seconds/month:
Automatic: 9R15, 9R16, 9R84, 9R86, 9R96, 9RA2, 9RA5
So, are Seiko watches accurate? I think we can answer that with a resounding yes! However bear in mind that the level of accuracy depends on the type of movement, with quartz being most accurate, Spring Drive next, and then mechanical. Incidentally Seiko has made other types of movement that are less common and not listed here – see my article about what movements Seiko watches use.
Note: The information here is correct as of January 2023. It might not include newer movements that Seiko has since released.
If you liked this, check out more articles about repairing, restoring and enjoying Seiko watches.