[VIDEO] Grand Seiko Redefines Accuracy – Again: Introducing the 9RB2 U.F.A. Spring Drive Caliber

2022: the Kodo constant force tourbillon. 2023: the Tentagraph hi-beat mechanical chronograph. 2024: the 9SA4 manual wound, hi-beat, dual-impulse escapement caliber, and Kodo Daybreak. It’s easy to forget that Grand Seiko has brought the proverbial heat to Watches & Wonders every year since the fair started, unveiling something that one could call “revolutionary” for the brand, if on varying scales. Well, it’s looking like 2025 will continue the trend with the introduction of Spring Drive Caliber 9RB2, the first caliber with U.F.A., or Ultra Fine Accuracy, designation.

Before proceeding, there are two important concepts to understand: Spring Drive and Grand Seiko’s history with acronyms (which, if you know, feel free to jump two paragraphs ahead). Starting with the former, the elevator pitch, which I will take from our article dedicated to the topic is “Spring Drive combines the best of mechanical watchmaking and the best of quartz timekeeping to create a state-of-the-art caliber that lacks the weaknesses inherent to both of these movements.” A bit deeper, Spring Drive movements use the energy stored in a traditional mainspring to drive their proprietary “Tri-synchro” regulator, which replaces the classic lever escapement. It consists of a glide wheel, the rate of which is controlled by an electromagnetic brake, and is essentially regulated by an integrated circuit with a quartz oscillator. The result is a mechanical movement with quartz-like accuracy and a perfectly smooth sweeping seconds hand.

The second concept pertains to Grand Seiko’s use of the acronym V.F.A., which stands for Very Fine Adjusted. In 1970, Grand Seiko launched the (6185-8000) featuring these letters on the dial, indicating that it had undergone rigorous regulation. This set it apart from their already-chronometer-beating standard of -3/+5 seconds per day, with a standard of -2/+2. Still exceptional to this day, these watches were truly a shot across the bow of the Swiss watch industry at the time.

With that out of the way, you are primed for Grand Seiko’s latest and greatest, the 9RB2 U.F.A. caliber. Spring Drive movements are already more accurate than standard mechanical movements, rated at -/+15 seconds to -/+10 seconds per month, caliber depending. The U.F.A. standard is not measured per day or month but rather per year, with an astonishing -/+20 seconds annually. As such, Grand Seiko is claiming the 9RB2 is the “most accurate wristwatch movement powered by a mainspring today.”

Not too shabby and a deserved tribute to the V.F.A. standard. This higher accuracy was achieved through new quartz processing methods (Seiko grows and ages its own quartz crystals), and a newly designed integrated circuit. Furthermore, the 9RB2 is the first Spring Drive caliber with a regulation switch, allowing for further after-sales adjustment. Other stats include 72 hours of power reserve, movement power reserve, and 34 jewels.

And of course, with a new movement comes new watches, and surprisingly, new cases, a new dial texture, and a first for Grand Seiko that has been a long time coming. The SLGB001 and SLGB003 are part of the Evolution 9 Collection and feature a 37mm in diameter and 11.4mm thick take on the sporty E9 case design with 18mm lugs. I was surprised to see this, as Grand Seiko had just launched the 38.6mm version last year with the SLGW003, which I had assumed we would see iterations of for W&W this year. That said, this new case size is very exciting, especially as it’s an automatic Spring Drive with 100m of water resistance. Having tried it on, it looks and wears a bit bigger than it sounds, and has a sporty presence.

Both watches have a new dial design called “ice forest.” Reminiscent of frost on a window, the stamped texture features layered “crystal” forms set at angles, covering the dial from edge to edge. It’s an appealing new texture that is slightly more subtle than recent birch patterns. Both dials are cool, metallic silvers, but the 001 has a deeper blue hue. The watches primarily differ in material, as the 001 is 950 platinum, and the 003 is high-intensity titanium.

The 003 introduces one more bit of newness that I’m sure Grand Seiko fans will be happy to see. The high-intensity titanium bracelet is the first and currently only Grand Seiko bracelet with a micro-adjust clasp. Yes, you heard that right: micro-adjust. A simple but proprietary mechanism offering 6mm of adjustment in three stops, it expands with the watch off and then tightens when on, much like Tudor’s T-Fit. Combined with the low weight of titanium, it should make for a very comfortable wear. When and how this will roll out to other bracelets has not been announced yet.

The SLGB003 is priced at $10,900, which surprised me. Given the new movement and bracelet, I expected it to be at least 12 or 13k, as last year’s SLGW003 was $11,000. That has a different movement and is also made of brilliant hard titanium, rather than high intensity, which must account for the difference. Either way, I’m not complaining about it, and it is in line with the other full titanium Evolution 9 Series watches, like the SLGA019 “Lake Suwa.” The SLGB001 is priced at $39,000 and is limited to 80 pieces worldwide. Both watches will be available beginning in June of this year. Grand Seiko