The Hi-Beat Goes On: Grand Seiko Unveils New Calibers for its 60th Anniversary

On December 18, 1960, Japanese watchmaking giant Seiko released the first Grand Seiko timepiece, which became legendary for reaching new heights of precision, durability, legibility, and ease of use. This year, the Grand Seiko brand — once Japan’s best-kept horological secret, now a worldwide phenomenon — celebrates 60 years by releasing a host of new models and calibers. So far, we’ve covered four limited editions with signature blue dials and three models re-creating the very first Grand Seiko watch. Today, we drill down into the two brand-new Grand Seiko calibers debuting this year, and reveal the watches that will contain them.

Grand Seiko SLGH002 with caliber
The Grand Seiko SLGH002 houses a new Hi-Beat caliber in its yellow-gold case.

The new Grand Seiko Hi-Beat Caliber 9SA5 is the latest evolution of the groundbreaking 9S mechanical caliber introduced in 1998, noteworthy for combining a 36,000-vph frequency with a lengthy 80-hour power reserve. Grand Seiko’s watchmakers set out “to strike the perfect balance between precision, power, and size” in the new movement, which also delivers a precision rate of +5 to -3 seconds per day. It achieves these results thanks to three technical advances. The first is an in-house-developed dual-impulse escapement, in which the wheel transmits power directly to the balance for increased efficiency. Another is a newly developed free sprung balance that is more resistant to shock and friction than its predecessor and uses an overcoil rather than a flat hairspring to improve isochronism, Finally, Caliber 9SA5’s innovative, horizontal gear train allows the overall movement to be 15 percent slimmer than existing Grand Seiko Hi-Beat calibers.

Grand Seiko Caliber 9SA5
Grand Seiko Caliber 9SA5

Caliber 9SA5 stores its 80-hour power reserve inside two barrels, arranged in sequence, and its date change is virtually instantaneous. Also as par for the course for Grand Seiko, it boasts a variety of high-end finishing and aesthetic flourishes inspired by the company’s native Japan. The movement’s bridge has a a gently curving outline inspired, the brand says, “by the shapes of Mt. Iwate and a bend in the Shizukuishi River,” which runs near the Grand Seiko Studio Shizukuishi, the watchmaking atelier where the caliber is made.

Grand Seiko Caliber 9SA5 escapement
The new dual impulse escapement transmits energy directly to the balance.

The new movement makes its debut in a limited-edition timepiece (100 pieces) that harks back to the very first Grand Seiko watch of 1960. Its 18k yellow gold case is 40 mm in diameter and features slightly wider lugs for a more solid fit on the wrist. The hour hand and hour markers are larger and more prominent than on current models, as they were in that original watch; the hands, markers, Grand Seiko “GS” logo, and the frame around the 3 o’clock date window are all in yellow gold. Mounted on a brown crocodile strap with a gold folding clasp, the watch will be available in August 2020 and will retail for $43,000.

Grand Seiko SLGH002 LE - front
The 60th Anniversary Limited Edition is limited to 100 pieces.

The other new caliber for 2020 hails from Grand Seiko’s Spring Drive series, introduced in 1999, which combines quartz and mechanical elements for a high level of accuracy. The new caliber 9RA5, successor to the existing caliber 9R6, takes this technology to the next level, delivering a power reserve of five days — a 60 percent increase from the current caliber’s level. It also offers an even higher monthly precision rate of +/- 10 seconds per month, up from +/- 15 seconds; a more rapid date change, and even a reduction in thickness, from 5.8 mm to 5 mm.

Grand Seiko SLGA002 - angle
The newest Spring Drive caliber makes its debut in the Grand Seiko SLGA002, a professional diver’s watch.

The new caliber features a repositioning of the Magic Lever — a Seiko invention dating to 1959 that uses energy generated by the movement of the rotor in both directions to boost the efficiency of the winding system — away from the center to reduce its thickness. The stem and crown are placed toward the back to lower the center of gravity, while the gear train is closer to the center, held by a one-piece central bridge that aids in the movement’s enhanced rigidity and shock resistance.  The impressive 120-hour power reserve is held in two mainspring barrels of different sizes, better for torque and for optimizing the use of space.

Grand Seiko Caliber 9RA5
Grand Seiko Caliber 9RA5

Caliber 9RA5 is also the first Spring Drive movement equipped with a sensor to monitor its internal temperature and to compensate for any related changes in oscillation rate of the quartz crystal. Vacuum-sealed together, the oscillator and the sensor are protected from the ill effects of humidity, static electricity and light interference, all factors that could affect the movement’s accuracy. Like its all-mechanical sibling, this Spring Drive movement has distinctly Japanese inspirations in its finishing, particularly the jewels, described as reflecting the stars that shine brightest in early winter in the mountains where it’s made, and the surface treatments whose texture is reminiscent of winter frost.

Grand Seiko Caliber 9RA5 barrels
Two different-sized barrels store the movement’s five-day power reserve.

One of Grand Seiko’s popular divers’ watches has the honor of being the first to host this new caliber, housing it inside a 46.9-mm case in high-intensity titanium. Water-resistant to a professional-grade 600 meters, the case, its rotating dive-scale bezel, and its high-definition sapphire crystal are designed for easy and safe disassembly for maintenance. On the dial, the power reserve is displayed on an indicator at 10 o’clock divided into five increments that let its user know at a glance how many days of power are left in his watch. Mounted on a steel bracelet with a three-fold clasp, along with an interchangeable blue silicone strap, the watch will be available worldwide in August 2020. It is limited to 700 pieces and will be priced around $11,100.

Grand Seiko SLGA002 - front
The divers’ watch is limited to 700 pieces and boasts water resistance of 600 meters.
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