Grand Seiko has revealed what it claims to be the most accurate mainspring-powered watch ever made at Watches and Wonders.
Called the SLGB003 and part of the new Evolution 9 Collection, the titanium watch is driven by a new movement called the Caliber 9RB2. Whereas most watches are stated as being accurate to between about two and six seconds, plus or minus, per day, Grand Seiko says its new movement is accurate to plus/minus 20 seconds per year.
