Grand Seiko Releases Its Most Complicated Mechanical Watch Ever, And It’s A Special Tourbillon

Grand Seiko made its debut at Watches & Wonders this spring by debuting its first tourbillon and its most complicated watch ever, the Kodo Constant-Force Tourbillon. Seiko was among the luxury brands that decamped from Baselworld to join the Watches & Wonders event in Geneva for the first time this year. They also included Rolex, Patek Philippe, Chopard and Hublot.

Kodo is Japanese for heartbeat, a nod to the unique escapement, which includes a remontoir constant-force mechanism integrated on the same axis with tourbillon. The inner tourbillon carriage rotates once per minute, while the outer constant-force carriage follows its rotation at one-second intervals. The constant-force carriage has a ruby on one of its arms, which acts as a small seconds hand.

A constant-force mechanism is a small, secondary source of power in the form of a spring that regulates the power from the mainspring to the escapement. A mainspring loses power gradually and therefore provides less and less consistent power to the escapement. The smaller spring ensures the remaining power is served in regular doses so the watch’s high accuracy remains stable for longer. Combining both a remontoir and a tourbillon means the movement accounts for both positional errors and variation in energy supply, a rare combination in high watchmaking. The watch also incorporates a hacking function so that the rotating tourbillon carriage can be stopped when the crown is pulled out, allowing the time to be adjusted to the precise second.

Grand Seiko says each movement is tested for 48 hours in each of six positions and at three temperatures – twice as long as the industry standard. The performance characteristics of each movement are defined in the individual certificate provided with every watch. And here’s a final fun touch: The watch comes with a calfskin strap treated in the same traditional way that was once used to create the highly durable armor used by Samurai. It painted by hand with Urushi lacquer. The case is made from a combination of 950 platinum and Brilliant Hard Titanium. The Grand Seiko Kodo Constant-Force Tourbillon is a limited edition of 20 pieces, priced at $350,000 each.