This year, Revolution turns 20. Two decades of chronicling watches, people and ideas have given us a front-row seat to a remarkable story: how an age-old craft has both preserved its soul and reinvented itself for the 21st century. To celebrate, we’ve chosen over 100 names and milestones that, for us, define the era so far. From leaders to watches, you can see the whole list here.

In 2004, Grand Seiko released the SBGA001. On the surface, it was a pretty simple watch. 41mm, steel case on a utilitarian bracelet, with an unremarkable reference number for a name and a particularly mercurial champagne dial. But on closer examination, there’s one thing on the dial that stands out — the seconds hand. It doesn’t tick like quartz, or move in a stuttering sweep like a conventional automatic — it glides.

Grand Seiko SBGA001 (Image: Bernard Watch Co.)

That gliding motion is the hallmark of Spring Drive — an incredible technology with a long history, that finally reached maturity in 2004, with the Caliber 9R65. The idea behind Spring Drive dates back to the 1970s, and an engineer named Yoshikazu Akahane, who, throughout his long career at Seiko, continued to work towards his dream of a watch that offered the accuracy of quartz combined with the autonomy of an automatic. In many ways, the concept of Spring Drive was sound, but ahead of its time. The first commercially produced Spring Drive calibers debuted in 1999 in a manual winding version, but it wasn’t until the automatic 9R65 of 2004 that Akahane’s version of perpetual quartz-like accuracy was finally achieved.

Caseback view (Image: Bernard Watch Co.)

The concept at the heart of Spring Drive was to combine three power sources: a traditional mainspring provides the power source, pushing kinetic energy through a gear train, which includes a unique component called a glide wheel. This wheel features a small magnet and generates a small amount of electrical power, which powers a quartz regulating crystal. An integrated circuit analyses this frequency and compares it to the speed of the glide wheel, sending an electromagnetic pulse to the glide wheel as necessary to brake it. Grand Seiko calls this the Tri-synchro regulator, an ingenious synergy of three energy sources that works as a virtuous circle to provide a smooth, regular motion that translates to the impossibly smooth glide of the Spring Drive.

Since the debut of the SBGA001, Grand Seiko has offered numerous iterations on their signature technology; indeed, any would argue that it was a Spring Drive watch, the SBGA011 aka the “Snowflake,” that was a watershed moment for Grand Seiko becoming a truly global brand. Grand Seiko has also improved upon the technology, with the Caliber 9R65 offering an unprecedented level of accuracy, with an annual rate of +/– 15 seconds a year, making it the most accurate watch with a mainspring.

Tech Specs: Grand Seiko SBGA001

Movement: Self-winding Caliber 9R65; 72-hour power reserve
Functions: Hours, minutes, seconds and date
Case: 41mm × 12.5mm; stainless steel; water resistant to 100m
Dial: Champagne-colored
Strap: Stainless steel bracelet