Chapter 3
Achieving Eight Days of Power Reserve
Spring Drive movements tailored specifically for Grand Seiko and crafted by the Micro Artist Studio
With their innovative mechanisms and intricate, handcrafted finishing, Calibers 9R01 and 9R02 were developed for the Grand Seiko Masterpiece Collection. Each takes a different approach to extending power reserve: Caliber 9R01 uses three sequentially linked barrels to house springs that can sustain the movement for eight days, while Caliber 9R02 uses the Torque Return System, which recycles the high torque of Spring Drive to wind the mainspring automatically, ensuring 84 hours of power reserve.
Calibers 9R01 and 9R02 were created at the Micro Artist Studio, which was established in 2000 inside Seiko Epson's Shinshu Watch Studio in Shiojiri City, Nagano. Here, expert watchmakers exercise the highest level of their skills in each task of the manufacturing process to create Japanese luxury wristwatches of exceptional beauty and quality.
An incredible eight days of power reserve and a design inspired by a magnificent landscape
A watch’s accuracy is something one doesn’t often notice until, eventually, it stands out – usually after some time using it. The development team believed that a long power reserve would ensure each timepiece could take full advantage of the high precision of the Spring Drive technology. Given that modern life runs in weekly cycles, their ideal was to achieve an extra day’s power reserve in addition to that base period—i.e., eight days.
Caliber 9R01 appeared in 2016, the first movement developed specifically for Grand Seiko at the Micro Artist Studio. With three barrels, eight days of power reserve, and breathtaking performance and beauty, it was a groundbreaking achievement for a manual-wound Spring Drive movement. Inside, its three barrels arranged in sequence minimized power loss during transmission; outside, it was exquisite to behold. The bridge that covers most of the movement traces the familiar contours of the iconic Mt. Fuji as seen from the highlands of Takabocchi, just a stone’s throw from Micro Artist Studio; the glide wheel represents the sun; the rubies are the sparkling lights of Suwa City; and the power-reserve indicator echoes the shape of Lake Suwa.
Craftspeople hand-apply a straight grain known as hairline finishing to the surface of the bridge, and the edges are all hand-polished. Meanwhile, the screws are tempered to a beautiful shade of blue. The result is an exquisite balance of performance and beauty.
The pinnacle of craftsmanship: fitting a movement with a long power reserve in a slender design
When it developed Caliber 9R02 in 2019, the Micro Artist Studio delivered a marvel of design and engineering, creating a movement with an 84-hour power reserve with a height of just 4mm, allowing it to power slender dress watches of classic proportions.
Thanks to the Dual Spring Barrel and the Torque Return System, the latter of which recycles power that would otherwise be wasted, Caliber 9R02 will run for 84 hours when fully wound. This elegant yet powerful movement is superbly engineered, it is true, but it is at least as impressive for its highly refined aesthetics. The bellflower motif (the official flower of Shiojiri City) on the barrel, the hairline finishing on the bridges, and the polishing on the edges are every bit as high-quality as the finishing of Caliber 9R01. Moreover, the inner angle of the larger of the two bridges of Caliber 9R02 is surely the pinnacle of watchmaking skill.
The sapphire crystal case back, which allows a view of the inner workings, makes this a mesmerizing work of art the wearer will wish to admire for years to come.
Masterpiece Collection
SBGD201
Caliber 9R01 powers the Masterpiece Collection SBGD201, whose case is Platinum 950 polished using the new Zaratsu polishing technique, resulting in a beautiful appearance with prominent edging that was previously not possible with platinum cases. The textured dial inspired by diamond dust, reminiscent of a winter morning in Suwa, has a unique composite finish that ensures high legibility while also providing beauty that shines in the light.
Masterpiece Collection
SBGZ003
A platinum masterpiece powered by Caliber 9R02, the SBGZ003 is configured so that the power-reserve indicator is located on the movement side of the timepiece, and thus visible through the sapphire crystal case back.
As the seconds hand glides across the dial, the wearer feels the natural flow of time in winter and the beauty of the natural world in its purest, pristine state. The hour and minute hands, as well as all of the hour markers, are made from 14-karat white gold, and the Grand Seiko logo, Spring Drive logo, minute markers, and Special Dial mark at the six-o’clock position sparkle like light on snow.
With its eight days of power reserve and outstanding artistry, the SBGZ003 is a landmark timepiece in both function and beauty. As the ultimate fusion of Japan’s exceptional mechanical and quartz watch technologies, the evolution of Spring Drive is an ongoing story of continuous advancement.
