Grand Seiko Kodo Constant-force Tourbillon SLGT005
Japanese luxury watch brand Grand Seiko presents the new Kodo Constant-force Tourbillon (reference SLGT005) in a limited edition of just 20 pieces.
Introduced 2022, the Kodo Constant-force Tourbillon is the first mechanical complication by Grand Seiko. This revolutionary watch combines a tourbillon and a constant-force mechanism as one unit on a single axis for the first time in horological history. Winning the Chronometry Prize at Grand Prix d’Horlogerie de Genève 2022, it represented a major milestone in the history of Grand Seiko.
The first edition of Kodo (SLGT003) expressed evening twilight through the delicate interplay of light and shadow. In comparison, the new version (reference SLGT005) uses light and shadow to evoke daybreak.
The silver toned movement components provide the new Kodo a subtle but bright appearance that accentuates the intricately constructed and layered parts. The beauty of the painstakingly hand-polished components is even more pronounced in the new timepiece.
For the first time in a Grand Seiko watch movement, blue sapphires are used for the jewels, adding an unexpected detail that is in perfect harmony with the design. Carefully examined and selected, the pale blue sapphires recall a beautiful dawn.
The open-work design not only reveals the beauty of the hand-finished movement, but the open spaces themselves have been carefully considered to reflect an important Japanese cultural and aesthetic value that respects the use of empty space. The use of open space is also reflected in the lugs, which harmonize with the case and add lightness to the design.
A subtle gradation of light is expressed through the use of different materials and various types of finishing. Platinum 950 forms the watch’s inner case, while Brilliant Hard Titanium forms the outer case, making the exterior highly resistant to scratches. The combination of the two materials creates a natural gradation and a long-lasting beauty. Some of the case parts in both metals are Zaratsu polished to a distortion-free mirror finish, while others have a hairline finish.
Beating inside, the Caliber 9ST1 incorporates a constant-force mechanism and a tourbillon set as one unit on a single axis. There are no wheels or other components between the two mechanisms, hence there is no loss or change in the torque transmitted from the constant-force mechanism to the balance wheel, which leads to a duration of approximately 50 hours for the constant-force mechanism and a highly stable amplitude for the balance. Together, these characteristics contribute to the movement’s high level of stable accuracy.
Moreover, the Grand Seiko Standard for Constant-force has been established for Caliber 9ST1 in which each movement is tested for a full 48 hours in each of six positions and at three temperatures, a duration that is double the main Grand Seiko Standard and the industry standard. Each movement is assessed over the course of 34 days to verify its accuracy.
The movement consists of approximately 340 components. Measuring 10mm in diameter, the world-premier complication that combines the integrated constant-force carriage and the tourbillon carriage are made of 100 parts. On the constant-force carriage, a single red ruby is placed on one of the arms indicating the seconds as they pass.
The rotating tourbillon carriage stops when the crown is pulled out, allowing the time to be adjusted to the precise second.
The inner tourbillon carriage rotates while the balance steadily vibrates at eight beats per second, and the outer constant-force carriage follows its rotation in exact one-second intervals. The sounds of the escapement and the once-per-second impulse of the constant-force mechanism harmonize with this visual rhythm to create a powerful yet gentle hum, which is set to a 16th note or semi-quaver.
The watch is offered with a leather strap created from a highly durable material that is specially treated in the same traditional way once used in samurai armor. But this time, a new white color was developed specifically for the new Kodo. The white strap is made through tanning with natural materials and then carefully hand-coated with layers of white urushi lacquer to create a deep sheen and a unique texture. A crocodile strap in charcoal grey also comes with the watch.
Each Grand Seiko Kodo Constant-force Tourbillon is designed and assembled by an elite group of Grand Seiko designers and watchmakers at Atelier Ginza, a creative studio established to deliver unique and innovative mechanical timepieces of the highest order. A logo identifying its production at Atelier Ginza is engraved on the movement.
The new timepiece belongs to the Grand Seiko Masterpiece Collection. Proposed in a limited edition of 20 pieces, it will be available at the Grand Seiko Boutiques starting in December 2024.
Model: Grand Seiko Kodo Constant-force Tourbillon, Reference SLGT005
Collection
Masterpiece Collection
Movement
Caliber 9ST1
Driving system: manual-winding
Frequency: 28,800 vibrations per hour (8 beats per second)
Accuracy: +5 to -3 seconds per day (when static for 48 hours)
Power reserve: 72 hours
Number of jewels: 44
Constant-force Tourbillon (Constant-force: 50 Hours)
Case
Platinum 950 and Brilliant Hard Titanium case
Diameter: 43.8mm
Thickness: 12.9mm
Box-shaped sapphire crystal with anti-reflective coating
See-through case back
Water resistance: 10 bar
Magnetic resistance: 4,800 A/m
Strap
Leather strap with Platinum 950 three-fold clasp with push button release
Double-sided crocodile strap included
Recommended retail price
Europe: €385,000
Edition
Limited edition of 20 pieces
