Introducing The New Grand Seiko Kodo Constant-Force Tourbillon

In 2022, Grand Seiko presented its first mechanical complication, the Kodo Constant-force Tourbillon, a revolutionary watch that combined a tourbillon and a constant-force mechanism as one unit on a single axis for the first time in horological history. As such, it represented a major milestone in the history of Grand Seiko and was recognized by the international watch community when it was awarded the Chronometry Prize at that year’s Grand Prix d’Horlogerie de Genève.

While the first Kodo expressed evening twilight through the delicate interplay of light and shadow that is central to Grand Seiko aesthetics, now, two years later, the new timepiece uses light and shadow to evoke daybreak. The delicate time when morning light begins to reclaim the sky is emphasized throughout the design, completing a portrayal of light and shadow that began two years ago.

The case measures 43.8 mm in diameter and has a height of just 12.9 mm. It is crafted from platinum 950 for the inner case and hard titanium for the outer case, lending it a luminous quality. Each component is meticulously hand-polished. The watch features a box-shaped sapphire crystal with an anti-reflective coating on the inner surface, along with a platinum caseback secured with six screws and a sapphire crystal, ensuring water resistance up to 100 meters.

The open-worked dial unveils the movement components, which are silver-toned, unlike the darker original model, as mentioned, imparting a sense of brightness. The hours and minutes are displayed on an off-center dial at 12 o'clock, while the seconds are located at 6 o'clock, a ruby on the constant-force cage acts as the second hand, with a power reserve indicator positioned at 8 o'clock.

the upper object with the three largest arms in the structure at six o'clock. This is the bridge over the tourbillon/constant-force mechanism. Below that is the constant force carriage, which has three arms, including the one with the ruby indicator. And below that is the tourbillon carriage, which also has three arms.

In 2020, Grand Seiko unveiled the "T0 Constant-force Tourbillon," an innovative movement concept merging a constant-force mechanism and a tourbillon into a single unit along a shared axis. This design introduces a remontoire constant force mechanism, acting as an intermediary power source between the mainspring and the escapement, thereby addressing the issue of a watch's speed fluctuating as the mainspring unwinds. The remontoire ensures a consistent supply of power to the escapement throughout the watch's power reserve, preventing excessive or insufficient power delivery at any stage. This synchronized power delivery, combined with the presence of the tourbillon, effectively mitigates both energy fluctuations and positional variances, offering a comprehensive solution to the inherent challenges.

The caliber 9ST1 is the result of this prototype. It is a manual-winding movement that beats at 28,800 vph, offering an accuracy of +5 to -3 seconds per day and a power reserve of 72 hours. For the inaugural occasion on a Grand Seiko timepiece, blue sapphires have been incorporated as jewels symbolizing the break of dawn. The movement comprises approximately 340 components, with 140 dedicated to the constant-force and tourbillon carriages.

The watch comes with a white strap exclusive to this model, crafted from white leather treated using traditional methods reminiscent of those once used for Samurai armor. Additionally, the watch includes a charcoal grey strap. This new Kodo is being released as a limited edition of 20 and will be available in December 2024, priced at USD 365,000, equivalent to 1,340,000 AED.

For more information, please visit Grand Seiko official website.