Since its founding, Grand Seiko has been dedicated to pushing the boundaries of watchmaking, striving for an unprecedented level of accuracy. The year 1969 saw the introduction of the V.F.A. (Very Fine Adjusted) designation, which represented a mechanical timepiece so precisely adjusted that it achieved an extraordinary monthly rate of ±1 minute. Then, in the late 1970s, the company set out to develop Spring Drive, a movement that would unite the traditional energy of a mainspring with the latest advancements in watchmaking technology. In 2004, this vision was realized with the debut of the Spring Drive Caliber 9R65, an automatic movement with a 72-hour power reserve and an exceptional accuracy rating of ±15 seconds per month—at the time setting a new standard for movements powered by a mainspring.
Today, that legacy evolves once more with the introduction of the Spring Drive Caliber 9RB2, which earns the new U.F.A. designation, standing for “Ultra Fine Accuracy.” This next-generation movement’s accuracy is not measured in seconds per day, week, or month, but by its performance over an entire year. With an astonishing annual accuracy of ±20 seconds, it stands as the most precise mainspring-powered wristwatch movement ever created (as of April 2025, based on Grand Seiko’s research).
This groundbreaking movement debuts in two timepieces from the Evolution 9 (otherwise known as E9) Collection: the SLGB001 (limited edition in Platinum 950) and SLGB003 (regular production in high-intensity titanium). The movement’s compact design allows for a case diameter of just 37mm, making the two watches in which it debuts the smallest ever to house a 9R series movement while ensuring both a refined and comfortable fit on the wrist.
Inspired by Nature, Engineered for Excellence: SLGB001 and SLGB003
To the east of the Shinshu Watch Studio, the Kirigamine Highlands transform into a breathtaking winter landscape, where frost-covered trees stand in silent beauty. Inspired by this natural wonder, the intricately textured dials of both SLGB001 and SLGB003 capture the essence of these ice-laden forests through expert finishing techniques that create pale blue tones that are subtle yet striking in their presence.
The high-intensity titanium SLGB003 features a silver-tinged blue dial, accented by a tempered blue seconds hand that evokes the crisp, crystalline serenity of a frost-covered landscape. In contrast, the Platinum 950 SLGB001 showcases a deeper blue, offering a refined backdrop for the seamlessly gliding silver-colored seconds hand. Together, these two creations bring the ethereal beauty of a distinctive frozen winter scenery to the wrist.
As part of the E9 Collection, these timepieces build upon Grand Seiko’s signature design philosophy, first established with the 44GS in 1967. With updated proportions, enhanced ergonomics, and improved wearability, the E9 Collection represents a refined evolution of this timeless design. The broad, faceted hands and prominent, grooved indexes ensure exceptional legibility, while the case construction highlights the exquisite interplay of Zaratsu-polished mirror surfaces and fine hairline finishes.
Measuring 37mm in diameter and 11.4mm in thickness, the smaller case sits with a low center of gravity and features a versatile form factor for a perfect fit on the wrist. The SLGB003 is paired with a bracelet equipped with a newly developed three-step micro-adjustment clasp that enables precise, tool-free sizing in 2mm increments. The SLGB001 is paired with a crocodile strap and a three-fold clasp crafted from Platinum 950 with elements of 18k white gold, adding an extra touch of refinement.
Both watches feature a box-shaped sapphire crystal with an anti-reflective coating on the inner surface, ensuring clarity and durability. With a water resistance of 10 bar and magnetic resistance of 4,800 A/m, these timepieces are as robust as they are precise.
Caliber 9RB2
The automatic Caliber 9RB2 delivers a 72-hour power reserve and operates with 34 jewels, enhancing its durability and long-term performance. The movement’s architecture incorporates a three-month-aged quartz oscillator, carefully processed and calibrated to enhance its stability, and a newly developed IC into a vacuum-sealed package to minimize external factors such as humidity, static electricity, and light. As with the 9RA series, the frequency of each individual quartz oscillator is measured at multiple temperatures, and the thermo-compensation data is programmed into the low-power IC to ensure precise temperature adjustments. Additionally, for the first time in Spring Drive history, the movement features a regulation switch, allowing adjustments during servicing to maintain peak accuracy over long periods of wear.
The artistry of the movement is revealed through a sapphire crystal case back, where mirror-polished bevels and fine detailing reflect Grand Seiko’s masterful craftsmanship. Inspired by the natural beauty surrounding the Shinshu Watch Studio, where Grand Seiko Spring Drive timepieces are made, the jewels set into the movement sparkle like the stars in a crisp winter night sky, while the delicate texturing evokes the frost-covered trees.
Availability
Both models will be available beginning in June 2025. The Platinum 950 SLGB001 is a limited edition of just 80 pieces and will be sold exclusively at Grand Seiko Boutiques. The high-intensity titanium SLGB003 will be available at Grand Seiko Boutiques and select retail partners worldwide.
