This is a great achievement for Grand Seiko as the most elegant handwound pieces always lacked a bit of refinement due to their case thickness. The new 9SA4 will be a game changer for future Seiko dress watch releases! The watch showcased in that video, the SLGW003G, is only 10.0mm thick!
I hope that in the future Grand Seiko will produce a movement that supports the outsized big date feature, both calibers 9s 9f 9r, but it seems that for the time being the calibers that are going up are 9r and 9s, especially from the development of the base caliber 9sa5, I also like the power reserve indicator feature ,,, good job for grand Seiko
@@HRM.HOmega is using silicone hairsprings, and that's traditional watchmaching.But I am sure GS will come up with a high grade antimagnetic solution, like they have for some of their 9F movements.