Grand Seiko Tentagraph SLGC006

Grand Seiko has introduced a new limited edition mechanical chronograph, the Tentagraph SLGC006, as part of its esteemed Evolution 9 Collection. This release represents a confluence of the brand's most advanced watchmaking technologies and its deeply rooted design philosophy, which draws inspiration from the natural landscapes of Japan. The timepiece is a technical showcase, housing the brand's first in-house mechanical chronograph movement, the Caliber 9SC5, within a case that blends multiple high-performance materials. Limited to just 300 pieces worldwide, the SLGC006 is a statement of capability from the watchmakers at the Grand Seiko Studio Shizukuishi.

The foundation of Grand Seiko's identity rests on a relentless pursuit of precision, legibility, and a distinct aesthetic. From its inception, the brand's goal was to create the ideal watch, a goal that required complete control over every facet of production. This led to its status as a true manufacture, an entity that designs, develops, and produces all components, from hairsprings and movements to cases and dials, entirely in-house. This integrated approach allows for a level of synergy and quality control that is central to the character of every Grand Seiko timepiece, ensuring that each element is optimized to work in perfect harmony with the others.



This particular model is a product of the Evolution 9 design philosophy, which was established to define the future of Grand Seiko's grammar of design. This style is not merely an aesthetic choice but a functional one, built on principles that enhance the user's experience. Key characteristics include cases with complex, alternating brushed and polished surfaces, wide lugs that provide a stable presence on the wrist, and dials that prioritize instant and unambiguous legibility above all else. The Evolution 9 style is a modern interpretation of the brand's heritage, creating watches that are both visually striking and eminently practical.

The case of the SLGC006 is a sophisticated assembly of modern materials, measuring 43.2mm in diameter with a thickness of 15.4mm and a lug-to-lug distance of 51.5mm. The primary material is high-intensity titanium, a proprietary alloy used by Grand Seiko that is lighter and more scratch-resistant than standard titanium, enhancing comfort for a watch of these dimensions. The case architecture features the sharp, faceted lines characteristic of the Evolution 9 style, with surfaces finished using the brand's signature Zaratsu polishing technique. This method, performed by hand, creates distortion-free, mirror-like surfaces that contrast sharply with the delicate hairline brushing applied to other facets, creating a dynamic play of light and shadow.

Adding to the material palette are key functional and aesthetic components. The fixed bezel, which features a tachymeter scale for measuring speed, is crafted from black ceramic. This material is chosen for its extreme hardness and resistance to scratching, ensuring the legibility of the scale remains pristine over time. Providing a warm and distinctive contrast to the cool gray of the titanium and the deep black of the ceramic are the chronograph pushers and the screw-down crown, which are rendered in 18k rose gold. This touch of precious metal elevates the watch's appearance, creating a visual link to the unique color of the dial.



The dial itself is perhaps the most captivating feature of the SLGC006. It presents a rich, copper-pink hue intended to evoke the sight of Mt. Iwate as it is bathed in the light of the morning sun. This mountain is a constant presence, visible from the windows of the Grand Seiko Studio Shizukuishi where the watch is made. The dial is not a flat color but features a complex, radial pattern with a rough, organic texture. This pattern is directly inspired by the ridgelines of the volcanic peak as seen from above, giving the dial a sense of depth and history that connects the watch directly to its place of origin.

Functionality and legibility are paramount on this complex display. The chronograph functions are laid out in a traditional three-register format, with a 30-minute counter, a 12-hour counter, and a running seconds sub-dial. To enhance readability, the sub-dials are slightly recessed, creating a multi-layered effect. The hour markers are large, multi-faceted, and deeply grooved, designed to catch light from any angle. The hour and minute hands are broad and sharp, with different finishes to distinguish them at a glance. Both the hands and the indexes are treated with LumiBrite, providing clear visibility in low-light conditions. The date window is discreetly placed between the four and five o’clock positions, a deliberate choice that allows for all twelve hour markers to remain fully intact, preserving the dial's symmetry and ensuring the sub-dials are unobstructed.

At the core of this timepiece is the Caliber 9SC5, a movement that represents a milestone for Grand Seiko. The name "Tentagraph" is a neologism derived from the movement's key attributes: TEN beats per second, a Three-day power reserve, Automatic winding, and chronoGRAPH. This caliber is the culmination of decades of expertise in mechanical watchmaking at the Shizukuishi facility, combining high performance with endurance in a way that is exceptional within the industry.



One of the most significant specifications of the Caliber 9SC5 is its high-frequency beat rate of 36,000 vibrations per hour, or 10 beats per second. This rapid oscillation of the balance wheel allows for greater precision and stability against external shocks. For a chronograph, this is particularly important as it enables the measurement of elapsed time in intervals of one-tenth of a second, offering a higher resolution of timing than more common 6 or 8-beat-per-second movements.

Despite this energy-intensive high frequency, the Caliber 9SC5 boasts an impressive power reserve of approximately 72 hours, or three full days. What is particularly noteworthy is that this duration is maintained even when the chronograph function is actively running. Grand Seiko achieved this industry-leading performance for a 10-beat chronograph through the synergy of two key technologies: a pair of twin barrels that store more energy from the mainspring and the highly efficient Dual Impulse Escapement.

The Dual Impulse Escapement is a proprietary Grand Seiko innovation that significantly improves the efficiency of power transmission to the balance wheel. It cleverly combines a traditional indirect impulse with a direct impulse, where power is transferred directly from the escape wheel to the balance. This mechanism overcomes the inherent loss of efficiency typically associated with high-beat movements, allowing the Caliber 9SC5 to sustain its rapid oscillations for an extended period without depleting the mainspring's energy too quickly.

To ensure the precise and reliable operation of the chronograph, the movement employs a column wheel and a vertical clutch system. The column wheel is a sophisticated component that governs the start, stop, and reset functions, providing a crisp and satisfying tactile feedback through the pushers. The vertical clutch engages the chronograph mechanism, preventing the jarring "jump" of the seconds hand that can occur with horizontal clutch systems. This ensures a smooth start to timing and eliminates the potential for initial inaccuracy.



When the chronograph is reset, a component known as the three-pointed hammer comes into play. This single, integrated part is designed to strike the heart pieces of the seconds, minute, and hour counter cams simultaneously. This ensures that all three chronograph hands snap back to their zero position instantly and in perfect unison, a testament to the movement's precise engineering.

Further enhancing the movement's long-term stability and precision is the Grand Seiko Free-sprung Balance. This design forgoes a traditional regulator for rate adjustment. Instead, precision is fine-tuned by adjusting four small screws on the balance wheel itself. This system is more resilient to shocks and maintains its accuracy for longer periods. Paired with this is a specially shaped overcoil, whose unique curve was determined after more than 80,000 computer simulations to optimize performance and isochronism in every possible orientation.

Even the date change mechanism was re-engineered for this high-end caliber. The Caliber 9SC5 features a new movable "date finger," a small, complex component produced using MEMS (Micro-Electro-Mechanical Systems) technology. This advanced manufacturing technique allows for the creation of intricate parts with high precision and durability, resulting in a date change that is noticeably faster than in previous movements.



The watch is fitted with a bracelet constructed from the same high-intensity titanium as the case, maintaining a consistent look and feel. The links are designed with the principles of the Evolution 9 style, featuring broad, flat surfaces with both brushed and polished finishes that articulate comfortably around the wrist. The bracelet secures with a three-fold clasp equipped with a push-button release mechanism for ease of use and security.

The Grand Seiko Tentagraph SLGC006 is scheduled for release in October 2025 with a retail price of $22,600 USD. As a limited edition of 300 units, its availability will be restricted. The watch will be sold exclusively through Grand Seiko Boutiques and authorized Grand Seiko Salons, targeting collectors and enthusiasts who appreciate the brand's unique blend of high-technology watchmaking and artistic expression.

Case: High-intensity titanium with 18k rose gold pushers/crown and a ceramic bezel. Diameter 43.2mm, Thickness 15.4mm, Lug-to-lug 51.5mm. Box shaped sapphire crystal, see-through screw case back, screw-down crown. Water resistance 10 bar.

Movement: Caliber 9SC5 "Tentagraph". Automatic with manual winding, 36,000 vph (10 beats/sec). Power reserve approx. 72 hours. 60 jewels. Accuracy of +8 to -1 seconds per day (normal usage). Chronograph with 30-minute and 12-hour counters.

Dial: Copper-pink color with a radial texture inspired by the ridgeline of Mt. Iwate. Features LumiBrite on hands and indexes.

Strap: High-intensity titanium bracelet with a 23mm band width. Features a three-fold clasp with push button release.

Price: USD $22,600.00

Reference Number: SLGC006

Notes: Limited edition of 300 pieces for an October 2025 release. Features Grand Seiko's first in-house mechanical chronograph movement, the Caliber 9SC5. The 72-hour power reserve is maintained even with the chronograph function active.