Grand Seiko's 60th anniversary in 2020 opened a new chapter in design and movement. The Japanese brand unveiled the Evolution 9 style as well as high-beat Caliber 9SA5.
The Evolution 9 family now welcomes a mechanical chronograph powered by Caliber 9SC5 that sets a new standard in elapsed time measurement.
The new sports watch is named Tentagraph to reflect on its high-beat rate of 10 times per second, long power reserve of three days, and its automatic chronograph function.
Evolution 9 speaks to a new generation while preserving the sensual play of light and shadow of the Grand Seiko style.
The design is based on three principles regarding aesthetics, legibility and comfort, and nine elements including those inherited and evolved from the Grand Seiko style, as well as new features on the case and bracelet.
The Evolution 9, for instance, is characterised by Zaratsu polished, distortion-free mirror and delicate hairline finishes that give the case a harmonious glow.
The Tentagraph's 43.2mm case and bracelet are made of high-intensity titanium, which is about 30% lighter and more scratch resistant than stainless steel. The bezel is in ceramic to further protect the watch from scratches and enhance durability.
The curved profile, wide lugs and low centre of gravity ensure comfort on the wrist.
The Tentagraph and other mechanical watches are hand assembled at the Grand Seiko Studio Shizukuishi in Iwate Prefecture.
The dial boasts the signature Mt Iwate pattern, inspired by ridged contours of the nearby mountain visible through the windows of the watchmaking studio. Its gentle blue hue evokes the night sky above Mt Iwate.
A running seconds sub-dial along with 12-hour and 30-minute chronograph counters are respectively positioned at 3, 6 and 9 o'clock. Hands and indexes are coated with Lumibrite to enhance night legibility.
In terms of precision engineering, Grand Seiko builds on its expertise in high-beat movements for the Tentagraph.
The heritage dates back to the 1960s, when its engineers identified 36,000 oscillations per hour (10 per second) as the rate needed to achieve both high accuracy and durability. A self-winding Grand Seiko carrying a 10-beat movement debuted in 1968.
Some four decades later in 2009, Grand Seiko introduced Caliber 9S85, which redefined high-beat watchmaking in precision, durability and reliability, thanks to newly-designed components, new materials and manufacturing technologies.
Three years ago Caliber 9SA5 became a foundation for engineering a whole new generation of Grand Seiko mechanical watches. The slimmer movement features a radical redesign of the escapement, free-sprung balance and gear train.
Based on this high-beat movement, the Tentagraph's new Caliber 9SC5 provides high accuracy when measuring elapsed time as well as the time of day.
Its energy-efficient escapement and two barrels allow the watch to run three days, even when the chronograph is in operation.
The movement's revolutionary Dual Impulse Escapement transfers energy to the free-sprung balance wheel. MEMS (Micro-Electro-Mechanical Systems) technology is used to ensure lightweight and durable parts, endowing the escapement with the increased energy efficiency to achieve the long power reserve.
Other elements include a vertical clutch, which eliminates any shuddering or jumping of the hands when the chronograph is engaged, while the column wheel delivers precise control of operation.
The Tentagraph is subjected to a longer testing procedure. As with all Grand Seiko mechanical movements, the time-of-day accuracy is assessed in six positions and at three temperatures over 17 days but, in addition, there are three more days of testing during which the accuracy is assessed in three positions while the chronograph is in operation.
Thus, in total, each Tentagraph movement is tested for 20 days to ensure that it meets Grand Seiko's accuracy of +5 to -3 seconds per day.
