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Calibre 9F Grand Seiko: The most accurate mechanical movement of this century

Updated: Dec 20, 2023

The mechanics used in Grand Seiko's Caliber 9F engine use Astron Quartz technology. This technology delivers higher performance and greater endurance. The advent of the Seiko Quartz Astron in 1969 marked the beginning of the Grand Seiko Caliber 9F, which remains state-of-the-art technology to this day and sets new standards of accuracy that rise to ten times higher than even the best mechanical precision watches. Thirty-five years after the release of the world's first quartz wristwatch, this wristwatch has been recognized by the IEEE (Institute Of Electrical And Electronics Engineersm Inc.), a technical professional organization based in the United States, as an important achievement and registered on the IEEE Milestone list.

The Caliber 9F quartz movement relies on a battery as a power source. This battery will then supply electricity to the oscillator and make vibrations proper 32,768 times per second. The integration circuit ( IC ) will detect vibration and send a time signal to the driving motor, then the driving motor will activate according to this timing signal, accurately rotating a series of gears and clock hands.

Changing the date display in the blink of an eye.

Through this mechanism, the date indicator driving wheel builds tension in the lever spring as it rotates, eventually releasing the stored energy when it reaches the location of the cam and driving the calendar wheel forward in the blink of an eye.

While some mechanical movements possess enough torque to deliver instant date changes, Grand Seiko was the first to pioneer the mechanism in a quartz movement.The task of aligning the Instant Date Change Mechanism to occur precisely at midnight falls upon Seiko's skilled craftsmen, who painstakingly set the mechanism by hand. In order to ensure that there is no situation in which the change occurs prematurely, the mechanism is set to activate within five minutes of the midnight.

The balance wheel on a mechanical watch is highly susceptible to the impact of gravity and wrist movement, but in a quartz movement, temperature changes are an impediment. As a major pioneer of wristwatches with the Quartz Movement, Grand Seiko innovated by creating a Regulation Switch mounted on the Caliber 9F in order to maximize the high precision of the wristwatch. The owner can make corrections in the settings of this regulation switch if the clock feels faster or slower. During the process, every movement of Calibre 9F is measured 540 times a day to ensure that variations in ambient temperature do not alter the watch's level of precision. Caliber 9F has a precision rating of ±10 seconds per year, one grad on the regulation switch equals 0.0165 seconds a day, or 0.5 seconds a month. It's no wonder that Grand Seiko is a mechanical watch with high accuracy compared to other mechanical watches.

Despite having an extraordinary level of complexity, every watch that uses Caliber 9F is assembled with proper procedural and inspection by craftsmen or women who have high skills. Doesn't appear like most other mechanical watches made with automatic movements, Grand Seiko has maintained its quality for the exclusivity of its watches.


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