[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...