Cover Grand Seiko Kodo Constant-Force Tourbillon

The Japanese manufacture has developed its own constant force mechanism and tourbillon for a limited edition timepiece

A mechanical watch needs to be "recharged" to regain optimal performance. A fully wound watch gradually loses its torque after some time, and this may also result in loss of time-keeping accuracy.

How does one maintain a steady rate of power delivery, and thus accuracy? There has been a number of solutions, one of them being the constant-force escapement. We've already seen this in Swiss watches like Girard-Perregaux, but this innovation appears for the first time in a Grand Seiko—specifically the Grand Seiko Kodo Constant-Force Tourbillon.

See also: Japanese Watches With Hidden Superpower

arrow left arrow left
arrow right arrow right
Photo 1 of 2 An openworked dial with platinum-titanium combination case
Photo 2 of 2 Close-up of the tourbillon and constant-force mechanism

The Japanese watchmaker has gone one step further by also incorporating a tourbillon, the gravity-cancelling complication to ensure better accuracy, in the new Caliber 9ST1. Both the constant-force mechanism and tourbillon are constructed on a single axis so that there is no loss in torque transmitted to the balance wheel. Tested relentlessly for 34 days, this remarkable combination proves that it can produce 50 hours of constant force on 72 hours of power reserve.

Grand Seiko has chosen to reveal the beauty of the movement with an openworked dial matched with a case of platinum and Brilliant Hard Titanium. The calf strap is painted by hand with urushi lacquer and treated for durability in a method traditionally used on a samurai armour.

The Grand Seiko Kodo Constant-Force Tourbillon—'Kodo' in Japanese means 'heartbeat'—is limited to 20 pieces.

NOW READ

King Seiko Makes a Strong Return

No Detail is Too Small for These 3 Japanese Watches

Watches & Wonders 2022: IWC Schaffhausen Unveils Its Metaverse