For six years after Grand Seiko was created in 1960, each watch was tested, in-house, to the highest international “chronometer” standard. However, in 1966, a new, higher, standard was set and, from that day to this, every Grand Seiko mechanical watch has been tested to ensure that it meets the “Grand Seiko Standard”.
In 1998, the bar was raised again. With the introduction of the first 9S calibers, new levels of performance had been reached and so a new and even higher “Grand Seiko Standard” was set. Today, before it is cased, each 9S mechanical movement is assessed over the course of 17 days in six different positions that reflect real-life usage and at three very different temperatures, 8, 23 and 38 degrees Celsius.
In 2023 when the Caliber 9SC5 TENTAGRAPH was developed, a further refinement was made to the standard, specifically for chronographs. It requires that every chronograph movement is tested for an additional three days with the chronograph in continuous operation.
Since 1966, the “Grand Seiko Standard” has been a challenging target that every Grand Seiko mechanical watch must reach. Times change but Grand Seiko’s commitment to industry-leading standards never will.
Caliber 9SA5 is Grand Seiko’s most precise mechanical movement in more ways than one. Thanks to its 36,000 vibrations per hour, its Dual Impulse Escapement and its Free-sprung Balance, it keeps time with a precision rate of +5 to -3 seconds a day, but its accuracy extends also to the way the date is presented.
In most watches, the date takes several hours to change but Caliber 9SA5 has a special mechanism that ensures that it changes within the blink of any eye. At the heart of this mechanism is a date indicator drive wheel that is just seven millimeters in diameter. Its springs and movable date finger, all made with MEMS technology, ensure that the date changes instantaneously. Even though it is hidden from view, this date-change mechanism is beautifully finished by Grand Seiko’s craftsmen and women for whom precision and craftsmanship are matters of equal pride whatever the component, visible or not. To watch the date change in a Caliber 9SA5 watch is to appreciate the value of their skill.