Seiko

The overcoil in Caliber 9SC5 has a special feature in its curved shape that was decided after more than 80,000 simulations, as a result of which its performance is optimized in every possible position. The secret lies in the precision manufacture of the components and in the extraordinary adjustment skills of the watchmakers at the Grand Seiko Studio Shizukuishi.

Hallmarks of a high-quality modern chronograph, a vertical clutch and a column wheel ensure high accuracy and operability. The vertical clutch eliminates any shuddering or jumping of the hands when the chronograph is engaged and enhances measurement accuracy, while the column wheel delivers precise control of the chronograph operation. The movement incorporates a three-pointed hammer, which ensures that, when the reset pusher is pressed, the hands return to zero instantly and in perfect synchronization.

The ideals of a Grand Seiko sports watch are readily apparent in this new chronograph. The powerful hands and prominent, grooved indexes of the Evolution 9 Style ensure supreme legibility. The chronograph seconds hand is gently curved down towards the dial so that the tip of the hand is as close as possible to the dial's markers and extends to the markings at the very edge of the dial. The minute hand is also gently curved to ensure the legibility of the time of day.

One signature of the Evolution 9 Style is its dial with redesigned indexes and hands, which have been created to achieve maximum legibility, allowing the wearer to check the time with just a glance. Everything about the Tentagraph’s chronograph and time-of-day displays has been thoroughly considered, from the placement of the hands relative to the indexes to the distance between the dial and hands. The recessed sub-dials sit a level below the main time-of-day display, enhancing the Tentagraph dial’s depth and legibility. And by placing the date between four and five o’clock, Grand Seiko’s designers ensured an index remains at each of the traditional hour positions while allowing for maximum readability for the time of day and the chronograph sub-dials.

The dial features Grand Seiko’s signature “Mt. Iwate pattern,” which takes inspiration from the ridged contours of the nearby mountain visible through the windows of the Grand Seiko Studio Shizukuishi, where the Tentagraph and all other Grand Seiko mechanical watches are hand-assembled and adjusted. The Mt. Iwate dial first appeared in 2006, and the pattern has since become deeply associated with Grand Seiko mechanical watchmaking. The majestic peak serves as an enduring inspiration for Grand Seiko, and its choice for the brand’s first mechanical chronograph is both symbolic and fitting. Combined with the gentle blue hue, the dial takes the imagination upwards towards the night sky above Mt. Iwate.

The Grand Seiko Tentagraph joins the Evolution 9 Collection and will be available at the Grand Seiko Boutiques and select retail partners starting in June 2023.