9S MECHANICAL MOVEMENT
After the wide acclaim given over many years to the Caliber 9S series of mechanical movements, it had long been Grand Seiko’s goal to push the boundaries back further and create a new mechanical movement with enhanced performance, just as the first 9S movement had done two decades before. The decision was taken to aim for a new 10-beat movement that would offer a greatly increased power reserve. This is how Caliber 9SA5 was born.
Automatic with manual winding
Mean daily rate*
+5 to -3 seconds per day
Normal usage accuracy
+8 to -1 seconds per day
36,000 vibrations per hour (10 beats per second)
Approximately 80 hours
Number of Jewels
-Dual Impulse Escapement
* Mean daily rate is a mean value of daily rates in a condition where the movement before assembly in a case is measured in six positions in a fixed manner under artificially controlled environment for 12 days.
The best Grand Seiko
mechanical movement ever created
Its birthplace was the Grand Seiko Studio Shizukuishi, where, for many decades, craftsmen and women have been responsible for the design and manufacture of all Grand Seiko mechanical watches. It was here, too, that the first 9S movement had been created.
The designers, engineers and watchmakers of the studio have two important assets at their disposal. First, they have inherited the tradition and accumulated know-how that has been built over decades as Grand Seiko has pursued its aim of “unflagging practical innovation” at the very highest level of the horological industry. Second, as a fully integrated “manufacture,” Grand Seiko has mastery of every aspect of the watchmaker’s art and has complete in-house control over every technical aspect of every single movement component.
Caliber 9SA5 is the direct result of the synergy of these two important assets, as its advanced functionality and its exquisite craftsmanship bear powerful testament.
The Dual Impulse Escapement increases the transfer efficiency of the power of the mainspring.
The Dual Impulse Escapement is a unique mechanism which combines “direct impulse,” where power is transferred directly from the escape wheel to the balance, with conventional “indirect impulse.” Thereby, it transfers power to the balance through the mainspring with increased efficiency. Conventional wisdom decrees that the more you increase the vibration rate of the balance, the lower the power transfer efficiency. This is because the escape wheel and pallet fork cannot keep up with the high oscillation speed. This challenge is met in Caliber 9SA5 as it has new components made with MEMS technology to increase the escapement efficiency. Connecting these to the twin barrels allows for 10 beats per second while delivering a continuous operation period of 80 hours.
The new Grand Seiko overcoil delivers precision and increased stability.
Caliber 9SA5 incorporates several new inventions, one of which is an overcoil. Created especially for this movement, this new overcoil has a unique 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.
The Grand Seiko Free-sprung Balance regulates the isochronism for long-term precision and stability.
For the fine tuning of the escapement’s precision, a new free-sprung system which does not have a regulator has been incorporated. The four screws on the side of the balance can be turned to adjust the moment of inertia of the balance, allowing for fine tuning to make the watch faster or slower. As there is no regulator, the durability of the hairspring is increased, as is the precision over time.
The Grand Seiko Free-sprung Balance is equipped with a mechanism that alters isochronism under fixed conditions when the stud at the end of the hairspring rotates. Thus, it is possible to adjust the isochronism while still remaining a free-sprung system with no regulator.
A balance with a large moment of inertia and twin barrels that enhance the power reserve
A power reserve of 80 hours is exceptional for a high beat movement. Caliber 9SA5 achieves this with a combination of two technologies. First, the Dual Impulse Escapement has high energy efficiency and, second, the twin barrels deliver more power. In addition, the durability of the movement is ensured by a mechanism which decreases the load placed on the front gear train. Since the twin barrels deliver more power, a 10-beat movement with a balance of large moment of inertia is made possible.
A faster date change, made possible by a new “date finger”
To reflect the high precision of the movement, a new date change mechanism was created for Caliber 9SA5 which ensures that the date changes much more quickly. It uses a new movable date finger whose complex shape and small size were made possible by MEMS technology, which also increases the precision of its operation and its durability.
A slim movement makes possible a watch that fits comfortably.
Remarkably, given its enhanced functionality, Caliber 9SA5 is slimmer than any existing Grand Seiko high beat movement. It is in fact 0.8mm or 15% thinner which allows the watch cases that house it to be slimmer and to sit more firmly on the wrist. This advantage is further enhanced by the new position of the crown which is lower and closer to the case back. This lowers the center of gravity of the watch and adds to the overall slimness of the watch when on the wrist.
A work of art, as beautiful as it is advanced.
The movement is as beautiful to behold as it is efficient in operation. From the very beginning, the designers were determined that the movement they were creating would have an aesthetic appeal that matched the high level of its performance and its ultimate appearance was always front of mind at every stage of its development. At first glance, it is the many curves and rounded surfaces that catch the eye and give the movement a warm and almost organic feel. This reflects the designers’ sense of their place in nature.
The bridge has a gently curving outline that is inspired by the shape of Mt. Iwate and a bend in the nearby Shizukuishi River that runs past the studio where the watch is made. The second impression the movement creates is one of texture. From every angle, different textures are to be seen in harmony. The side of the movement has a matte finish and a subdued tone that absorbs the light whereas the ridges, edges and screw holes are sharply cut and polished to a brilliant finish that sparkles with precision.
What makes 9S Mechanical special?
The concept of Grand Seiko was born from the desire to build the world's best watch, and the collection continues to push precision in mechanical watches to the limits of timekeeping technology.
As a true manufacture, Grand Seiko incorporates the latest technology alongside its breadth of craftsmanship to raise the art of watchmaking to its peak.
CALIBER 9SA5 MODELS
9S MECHANICAL MOVEMENT
- Hi-Beat 36000 80 HoursCaliber 9SA5
- MECHANICAL HI-BEAT 36000 GMTCaliber 9S86
- MECHANICAL HI-BEAT 36000Caliber 9S85
- AUTOMATIC 3-DAY POWER RESERVECaliber 9S68
- AUTOMATIC 3-DAY POWER RESERVE GMTCaliber 9S66
- AUTOMATIC 3-DAY POWER RESERVECaliber 9S65
- MANUAL-WINDING WITH A SMALL SECONDS HANDCaliber 9S63
- SMALL SIZE AUTOMATICCaliber 9S27