Cal. 9S63 is a hand-winding movement with small seconds and power reserve indicator from Grand Seiko. It is an unusual movement in many ways, though it is based on the common Cal 9S6x family. It was the first hand-winding movement introduced by Grand Seiko in 8 years when it first appeared in early 2019, and it remains the only mechanical movement in the line with a power reserve indicator.
Cal. 9S63 shares the same basic architecture as the hand-winding Cal. 9S64 but adds small seconds at 9:00 and a counter-clockwise power reserve pointer at 3:00. It was used only in the Grand Seiko SBGK series of watches.
Note that some initial coverage claimed it operated at 21,600 Ah but this is refuted by official Grand Seiko documentation.
Seiko 9S6x Family Overview
9S is the family of high-end mechanical watch movements used in the Grand Seiko and Credor watch lines. The current “3 days” 9S6x family debuted in 2006 with Cal. 9S67, and has replaced the Seiko 9S5x series over the following decade. The movement boasts 72 hours of power reserve thanks to a stronger Spron 510 or 610 mainspring and escape wheel and pallet form finished with MEMS technology.
Seiko boasts that these movements can deliver -3/+5 seconds per day accuracy in controlled static tests. On the wrist, the company claims -1/+10 second accuracy per day, and Seiko adjusts them in 6 positions. Adjustment is performed using a screw with index moving a mobile regulator for the flat hairspring.
The 9S family movements are constructed by hand at Seiko’s Shizukuishi Watch Studio in Morioka, Iwate Prefecture, Japan.
All watches in the 9S6x series feature hand winding, hacking seconds, and operation at 28,800 A/h. Most feature automatic winding with a central rotor mounted on five ball bearings. These use a conventional reverser wheel rather than the Seiko Magic Lever system found on the previous Cal. 9S5x series.
Seiko 9S6x Family
| Production | Models | Winding | Jewels | Date | Notes | |
|---|---|---|---|---|---|---|
| Cal. 9S61 | 2015-present | SBGR | Automatic | 33 | No | |
| Cal. 9S63 | 2019-present | SBGK | Manual | 33 | No | Power reserve at 3:00 Small seconds at 9:00 |
| Cal. 9S64 | 2011-present | SBGW | Manual | 24 | No | |
| Cal. 9S65 | 2010-present | SBGR | Automatic | 35 | Yes | |
| Cal. 9S66 | 2010-present | SBGM | Automatic | 35 | Yes | Central GMT hand |
| Cal. 9S67 | 2006-2010 | SBGL | Automatic | 41 | Yes | Power reserve at 3:00 |
| Cal. 9S68 | 2017-present | SBGR | Automatic | 35 | Yes | Larger size |
See Also: Seiko 9S6x Family