Monochrome Watches
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The Grand Seiko Hi-Beat 9SA5 “Shirakaba” SLGH005

Grand Seiko's innovative movement with Dual Impulse Escapement in a steel case with a handsome textured dial.

| By Brice Goulard | 4 min read |
Grand Seiko Heritage SLGH005 Calibre 9SA5 Shirakaba

Back in March 2020, Grand Seiko was celebrating its 60th anniversary and, in addition to expected special edition watches, the brand struck hard by presenting a fascinating movement, the Hi-Beat Calibre 9SA5 with multiple innovations, such as the novel Dual Impulse escapement. First presented in a gold case, followed by a limited edition in steel, this movement is now finding its way into the permanent collection with the watch we are presenting today. Meet the new Grand Seiko Heritage SLGH005 Calibre 9SA5 “Shirakaba”, with a dial that, typical to GS, reveals a superb texture.

The new “Shirakaba” SLGH005 is the first non-limited edition watch to be equipped with this innovative movement – we’re talking discreet innovations, but nevertheless impressive technology. As such, it is still based on the same architecture as the SLGH002 and SLGH003. The case, made of stainless steel, measures 40mm in diameter for a relatively reasonable thickness of 11.7mm (we know that GS isn’t the best in doing thin watches, but this one shows some welcome efforts). Classically sharp and faceted, it is inspired by the Series 9 Design, defined back in 1967 with the 44GS, which was an important part of the Grand Seiko Heritage Collection’s signature in the years to come. The bezel, for instance, shows a top flat surface with vertically brushed finishing and a polished bevel. The same design cues can be found on the lugs, with a combination of brushed surfaces and polished bevels on each side. Of course, all polished areas are done thanks to the celebrated Zaratsu (distortion-free) technique.

Grand Seiko Heritage SLGH005 Calibre 9SA5 Shirakaba

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Overall, this Grand Seiko Heritage SLGH005 is a nice mix of elegance and sportiness; a deliberately casual attire and more refined elements and more dynamic lines than previous Heritage models. The specifications make for a very usable watch, with a 100m water-resistance and magnetic-resistance of 4,800 A/m (classic for GS). It is worn on a brushed 3-link stainless steel bracelet, which features a three-fold clasp with push-button release.

Grand Seiko Heritage SLGH005 Calibre 9SA5 Shirakaba

The main novelty concerns the dial, which follows the brand’s tradition of textures inspired by natural elements. The new dial of the Grand Seiko SLGH005 is named “Shirakaba” or white birch trees – a reference to the forests that thrive in northern parts of Japan and that grow in profusion near the Grand Seiko Studio Shizukuishi where this watch is made. As such, the silvery-white dial shows a vertical texture that recalls the white bark of the birch trees, with a delicate shimmering effect. On top of the dial, the watch retains the same faceted and bevelled applied indexes (new to this series of watches) as well as redesigned hands that still feature a refined execution – mirror polished and faceted. The central seconds is blued for better contrast.

Where the Grand Seiko Heritage SLGH005 “Shirakaba” truly impresses is on the other side, under its sapphire caseback with GS lion emblem. It features an unprecedented development, the Dual Impulse, a brand new geometry for the escapement which differs from that used in the classic lever escapement. The escape wheel has a star shape with 8 arms, instead of a wheel with teeth. The main concept behind Grand Seiko’s Dual Impulse Escapement is that the locking and impulse functions are dissociated – a solution similar to the Audemars Piguet or the Omega Co-Axial escapements, for example. In one direction, power is transmitted directly to the balance (clockwise), as the roller receives impulse directly on its jewel. In the other direction, it receives an indirect impulse via the pallet fork, as in a traditional escapement.

Grand Seiko 60th Anniversary SLGH002 Hi-Beat Calibre 9SA5 Dual Impulse Escapement

Thanks to this dissociation of the locking and impulse functions, with friction occurring in only one direction, the escapement is more efficient (less friction means less energy required) and more wear-resistant. Calibre 9SA5’s new escapement works in conjunction with a new free-sprung balance that is more resistant to shock and friction and retains its precision for longer periods. This innovative escapement is used in a movement with a slim profile (5.18mm), long power storage (two barrels for 80h), a transversal bridge (for more resistance), and a high-frequency (5Hz or 36,000vph). The accuracy is rated at +5 to -3 seconds per day. The movement itself is also very pleasantly shaped and designed.

Grand Seiko Heritage SLGH005 Calibre 9SA5 Shirakaba

Availability & Price

The Grand Seiko Heritage SLGH005 Calibre 9SA5 “Shirakaba” is released as part of the permanent collection (not limited) and will be available in March 2021 at Grand Seiko Boutiques and selected retail stores worldwide. It will be priced at EUR 9,500.

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5 responses

  1. Isn’t 4800A/m pretty rubbish by current standards, with our lives being surrounded by iPad smartcovers and Magsafe chargers and all?

  2. @Litho – this 4800A/m measurement is the standard required by the ISO 764 norm (magnetic-resistant watches standard). However, this level (which corresponds to about 60 gauss) is indeed rather low compared to the 1,000 Gauss of Rolex or the 15,000 gauss of Omega.

  3. Stunning textured dial. I’ve said this before, but I still wish GH put a little more thought into type solutions on their dials.

    I’ve never loved the GS logo/fonts, but the font, arrangement, and size of the type, and for that matter, the words, below the hands does not say high end design to me. The details are best left for the case back or advertising. Hi-Beat, alone, would have been so much more confident.

    The old Hi-Beat type solution from the King Seiko dials was better, recognizable, and had good history. Small type matters.

  4. The watch is stunning, but ultimately not my style, like most GS watches. Put that movement – sans decoration but with same level of adjustment/regulation and include a 5yr warranty- into the next high-end SLA Prospex diver and I’ll be very, very interested.

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