Grand Seiko has unveiled a clutch of models to celebrate its 60th anniversary. However right now, we are focusing on one particular model, SLGH002 limited edition that features a brand new high beat haute horology movement, the “finest that Grand Seiko has created”. This is limited to just 100 pieces and will be available in boutiques this August.  

The Grand Seiko SLGH002 is cased in 18 K yellow gold

The commemorative timepiece has a fresh new design and while it channels all the virtues of a Grand Seiko case, there are subtle changes in-line with the evolution of the brand. The case is made from 18 k yellow gold and is 40 mm wide. Thanks to a slimmer new movement, the case profile is only 11.7 mm now. While the majority of the case has a brushed finish, the wide faceted bezels sport mirror-polished sides. The use of wider lugs ensures that the watch sits nicely on the wrist. The case is topped with a box-shaped sapphire crystal and is fitted with an exhibition caseback.

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The case of the SLGH002 is slim at 11.7 mm

The silver dial has the Grand Seiko logo, facetted indexes and even the calendar frame in 18 k yellow gold. Grand Seiko has also redesigned the characteristic dauphine hands, the hour hand is wide now and has a groove running through the middle. The watch is instantly recognizable as a Grand Seiko, but there is a palpable newness to the whole design.

The hour hand and indexes are wider now

The high beat movement has been a characteristic of modern Grand Seiko watches. The engineers at Morioka — where Grand Seiko watches are hand assembled — set out to create new movement that would strike a balance between precision, power and size without compromising any of these parameters. The new movement, the 9SA5 caliber has three key features never seen before on Grand Seiko models.

Caliber 9SA5 is a brand new high beat movement

A new escapement which riffs on the direct impulse escapement is used here for the first time. The escape wheel transmits power directly to the balance eschewing the lever escapement of conventional movements. However, unlike the co-axial escapement, the direct impulse happens only in one direction of the balance wheel’s motion. When the balance wheel moves in the opposite direction, it transmits the impulse through a pallet fork like in traditional movements. Grand Seiko calls this a Dual Escapement. This innovation has resulted in greater energy efficiency.

The new dual escapement used in the Caliber 9SA5

The balance wheel also uses an overcoil hairspring as opposed to the more conventional flatspring. The overcoil’s curve is shape by hand and was decided after more than 80,000 simulations with the result that its performance is optimized in every possible position. The big benefit to the user here is isochronism and better resistance to shock and friction.

The overcoil of the hairspring is curved by hand

The new caliber is also 15 percent slimmer than existing in-house high beat movements, thanks to the innovative horizontal layout of the barrel and gear trains. In addition to these three new components, Caliber 9SA5 has other features that contribute to its extraordinary performance. Two barrels, arranged in sequence, enhance the power reserve, the date change is virtually instantaneous and the positioning of the winding stem close to the rotor allows the watch to sit closer to the wrist. Caliber 9SA5 has a precision rate of +5 to –3 seconds a day and a power reserve of 80 hours.

The barrels are arranged in sequence and deliver 80 hours

The movement is as beautifully finished as it is efficient. The balance bridge’s curving outline is inspired by the shapes of Mt. Iwate and a bend in the Shizukuishi River that runs near the studio where the watch is made. Paired with a brown alligator leather strap with an 18K yellow gold buckle, the watch is limited to just 100 pieces and is priced at $43,000.