Seiko

Both watches are powered by Grand Seiko's latest hand-wound, high-frequency mechanical movement, the Caliber 9SA4. The new 9SA4 was made in pursuit of high rate stability and precision, beating 10 times per second; however, it also achieves a power reserve of 80 hours when fully wound thanks to Grand Seiko's highly efficient Dual Impulse Escapement and two barrels. It uses the Grand Seiko Free-sprung Balance and a hairspring with overcoil. As a result, Caliber 9SA4 benefits from the rate stability, resistance to outside interference, and high performance that have long characterized Grand Seiko’s high-beat movements. And, as with other Grand Seiko mechanical movements, 9SA4 is tested in six positions at three different temperatures over 17 days to ensure it meets the Grand Seiko Standard.

Not only was Caliber 9SA4 made to achieve the height of performance in high-beat watchmaking, but the movement was also designed with particular attention to the tactile, aural, and visual sensations encountered during hand-winding to create an ideal experience for the watch's owner.  Though the new Caliber 9SA4 has many of the same characteristics as 9SA5, nearly 40 percent of the base movement has been redesigned and reconstructed with careful consideration given to the tactile, aural, and visual sensations experienced during winding. The movement’s click, the part that holds the ratchet wheel to prevent the unwinding of the mainsprings, and the click spring, have been tailored to perfect their feel and sound, and the crown stops when the movement is fully powered. The click is in the shape of a wagtail, a bird recognized as special to Morioka, a city close to the Grand Seiko Studio Shizukuishi, where this and all Grand Seiko mechanical watches are crafted. Thanks to the redesign of the movement, the bird-like pecking motion of the click is visible to enjoy through the sapphire crystal case back during the hand-winding process. 

Together with the delicate finishing of the movement inspired by the Shizukuishi River, Caliber 9SA4 not only showcases the very best of Grand Seiko’s mechanical watchmaking capabilities but also captures the beauty of the studio’s natural surroundings. A power-reserve indicator on one of the movement bridges tells the watch’s state of wind. The movement achieves a higher winding efficiency thanks to a rearrangement of the gear train and redesign of the parts, so that Caliber 9SA4 achieves a power reserve of 80 hours with 15 percent fewer crown rotations than are required to achieve the same power for Caliber 9SA5 when winding it by hand. 

Caliber 9SA4

Driving system: Manual-winding

Frequency: 36,000 vibrations per hour (10 beats per second)

Accuracy (mean daily rate): +5 to -3 seconds per day

Power reserve: 80 hours

Number of jewels: 47

Specifications

18k yellow-gold case and clasp (SLGW004) and Stainless steel case and clasp (SLGW005)

Box-shaped sapphire crystal with anti-reflective coating on the inner surface

See-through case back

Water resistance: 3 bar

Magnetic resistance: 4,800 A/m

Diameter: 38.8mm, Thickness: 10.4mm

Crocodile strap with 18k yellow gold buckle (SLGW004) 

Crocodile strap with stainless steel buckle (SLGW005)

Pricing 

Recommended retail prices in Europe:

Limited edition of 200 SLGW004 at  €32,200

Limited edition of 1,200 SLGW005 at  €10,400