Grand Seiko Historical Collection Self-Dater Spring Drive Limited Edition SBGA103
In 1964, the 2nd generation of Grand Seiko was released. Manfactured at Suwa Seikosha (now Seiko Epson), the Grand Seiko Self-Dater was the 1st model of Grand Seiko not only to use a date display, but also water resistance and to use the Zaratsu polishing technique. For the 50th Anniversary of this model, Seiko has introduced 3 Spring Drive models, and 2 quartz models to commemorate this piece as a part of their Historical Collection. Also made at their Suwa facility, Shinshu Watch Studio, these limited editions feature higher accuracry calibers, the 9R15 for Spring Drive rating at +/- 10 seconds a month, and the Quartz 9F82 with +/- 5 seconds a year, both utilizing specially selected quartz crystals to ensure higher accuracy. These pieces symbolize the "Evolution of Practicality".
Drive system Spring Drive Caliber No. 9R15 Case stainless steel Case back See-through screw case back with sapphire crystal Glass High definition dual-curved sapphire crystal with anti-reflective coating Accuracy ±10 seconds a month Water resistance 10 bar Magnetic resistance 4800 A/m (60 gauss) Weight 105g Case thickness 13.2mm Case diameter 39.9mm Jewels 30 Remarks 18kt Grand Seiko Gold Medalion on Rotor