Grand Seiko Kodo Constant-force Tourbillon

Since its founding in 1960, Grand Seiko has carved a unique niche in the world of watchmaking. The Japanese brand has garnered a reputation for its meticulous craftsmanship, unwavering commitment to precision, and a distinct aesthetic sensibility. Their watches are not just timepieces, but rather miniature works of art, where form and function find perfect harmony.

In 2022, Grand Seiko unveiled the Kodo Constant-force Tourbillon, a watch that marked a significant milestone in the brand's history. This revolutionary timepiece combined a tourbillon and a constant-force mechanism as a single unit on a single axis, a first in the world of horology. The Kodo Constant-force Tourbillon was lauded by the international watch community, receiving the Chronometry Prize at the Grand Prix d’Horlogerie de Genève, the industry’s most prestigious award.



Building on the legacy of the first Kodo, Grand Seiko has now released a new iteration of the watch. This new timepiece evokes the delicate interplay of light and shadow that one witnesses during daybreak. The silver toned movement components and the carefully selected pale blue sapphires subtly hint at the pre-dawn light.

The interplay of light and shadow is further accentuated by the use of a variety of materials and finishing techniques in the watch’s construction. The case is a combination of two materials: Brilliant Hard Titanium and Platinum 950. The Brilliant Hard Titanium, twice as hard as stainless steel, ensures the exterior is highly scratch-resistant. These two materials are meticulously polished by hand using a combination of Zaratsu polishing, which creates a distortion-free mirror finish, and hairline finishing. This meticulous attention to detail ensures that the watch gleams with a subtle brilliance from every angle.

For the discerning watch collector, the Grand Seiko Kodo Constant-Force Tourbillon offers a compelling combination of technical innovation, breathtaking aesthetics, and enduring quality. The watch’s revolutionary movement, the caliber 9ST1, is a marvel of engineering. The complex design integrates the constant-force mechanism and the tourbillon into a single unit, eliminating the need for intervening wheels or gears. This not only simplifies the movement but also improves its efficiency, resulting in a remarkable 50-hour power reserve for the constant-force mechanism and a more stable amplitude of the balance wheel, contributing to the watch’s overall exceptional accuracy.



Beyond its technical prowess, the Kodo Constant-Force Tourbillon is a feast for the eyes. The intricate inner workings of the watch are a captivating sight. The constant-force carriage rotates at one-second intervals, while the tourbillon cage nestled within it completes a full rotation every minute. This mesmerizing dance of the mechanisms is a testament to the exceptional skill of Grand Seiko’s watchmakers.

The interplay of light and shadow extends to the watch strap. The new Kodo comes with a unique white calfskin strap, specially treated in the same traditional way used for samurai armor. The white color, a new development for Grand Seiko, was chosen to evoke the faint light of dawn. A contrasting crocodile strap in charcoal grey is also included.

The very core of watchmaking, the part that defines its fundamental job of keeping time, is regulating the release of energy from the mainspring. Traditional watch movements deliver power in inconsistent bursts, stronger when freshly wound, but gradually weakening. This leads to variations in accuracy over time. The constant-force mechanism addresses this challenge, ensuring a perfectly consistent supply of power to the escapement, regardless of the mainspring's tension. This translates into superior timekeeping precision across the watch's entire power reserve.



The tourbillon is another ingenious solution born from watchmakers' quest for accuracy. Invented by legendary watchmaker Abraham-Louis Breguet, it counters the effects of gravity on the balance wheel by placing it in a rotating cage. The constant rotation averages out the positional errors caused by gravity, further enhancing accuracy.

Grand Seiko’s revolutionary design combines these two complications in a way never seen before. The constant-force mechanism and tourbillon are integrated into a single unit, sharing the same axis of rotation. This integrated design eliminates friction points and streamlines energy transmission from the constant-force mechanism to the balance, resulting in an even more stable amplitude and improved energy efficiency.

The benefits extend beyond just theory. The Grand Seiko Kodo Constant-force Tourbillon boasts an impressive 50-hour reserve for the constant-force mechanism and an exceptional daily rate of +5 to -3 seconds, a testament to the effectiveness of the combined complications. For a watch enthusiast, these figures are more than just numbers – they're the guarantee of a timepiece that can be relied upon day after day.



The technical brilliance of the Caliber 9ST1 is complemented by the watch's mesmerizing aesthetics. Thanks to the integration of the constant-force and tourbillon components, the movement has an unexpectedly open construction for its complexity. This openness allows light to flow freely through both sides of the watch, highlighting the beauty of the intricate movement and its meticulous hand-finishing.

Each of the watch's components – plates, bridges, jewels – has been painstakingly adorned by skilled artisans. Their handiwork is most noticeable in the tourbillon carriage. The carriage is made of titanium, known for its lightweight properties, and it gleams with mirror-like brilliance. Its complex shape and meticulously polished edges, visible through the caseback, are evidence of countless hours of dedication to finishing and detail.

The new Grand Seiko Kodo Constant-force Tourbillon is a testament to the Japanese brand's unceasing pursuit of innovation and perfection. Its revolutionary movement is a masterpiece of precision engineering, executed with a level of craftsmanship synonymous with the Grand Seiko name.

The Kodo isn't merely a technical marvel; it carries within it the spirit of the traditional Japanese concept of "monozukuri," the art and science of manufacturing. Inherent in the philosophy of monozukuri is an unwavering commitment to meticulousness and the endless refinement of a product. Each element of the watch reflects this spirit, from the intricate finishing to the combination of high-performance materials.



Of course, this level of watchmaking comes with a limited availability (20 pieces worldwide!) and a cost that puts it in the category of a collector's dream. Yet, the innovation showcased in the Kodo will inevitably influence future Grand Seiko timepieces, bringing the same level of precision and beauty to perhaps more accessible offerings in the years to come.

The Kodo Constant-force Tourbillon isn't just another wristwatch; it's a symbol of the unwavering spirit of innovation that continues to drive Grand Seiko to challenge the boundaries of traditional watchmaking. It's a testament to the human pursuit of excellence and our boundless capacity to bring beauty married with technical mastery into the world.