Grand Seiko Evolution 9 UFA 37mm

Since Grand Seiko's founding in 1960, the relentless pursuit of high accuracy has been central to its identity. This commitment led to the development of Spring Drive in the late 1970s—a groundbreaking fusion of traditional mainspring energy and cutting-edge electronic timekeeping. In 2004, the Spring Drive Caliber 9R65 debuted with a monthly precision of ±15 seconds. Now, Grand Seiko sets a new benchmark with the Spring Drive Caliber 9RB2, earning the new U.F.A. (Ultra Fine Accuracy) designation. With an astonishing annual accuracy of ±20 seconds, it stands as the world’s most precise mainspring-powered wristwatch movement to date.*

*As of April 2025, based on Grand Seiko’s research.