AndCavanaugh
515
Seiko Epson goes by JIS standard no. B7025 for rating accuracy, which requires a few years of crystal aging date that didn't exist when the 9RA movements were launched
Seiko Epson released a technical paper on the 9RA movements years ago, they knew the 9RA movements could perform to +/-10 seconds a year when new.


You can access a PDF of the paper from this site, but it is in japanse.
www.jstage.jst.go.jp
Congrats!
By: Derreck : September 13th, 2025-13:58
It’s a great size at 37mm instead of all these 40-42s, much more classical looking. If you can, please let us know in a couple months the real accuracy of the movement. The Japanese generally downplay a lot the actual precision of their movements, for exa...