The
link hand-wound caliber 9S64 is one that we have encountered before it was
link first deployed by Grand Seiko all the way back
link in 2011 where it was used for the first time in the SBGW040 First Grand Seiko LE and the firm used it in the 2017 limited editions as well as the 2020 full production models. The version of 9S64 used in SBGW260 has had some noticeable upgrades over those versions of the movement.