Grand Seiko Heritage Calibre 9SA5 Platinum SLGH007J

In March 2020, Grand Seiko celebrated the 60th anniversary of its foundation by introducing a newly designed watch featuring a cutting-edge and advanced 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, and a few weeks ago in a non-limited “Shirakaba” edition, both the design and movement returns this year in a high-end limited edition made of platinum and adorned by a stunning dial reflecting the spirit and vision of Kintaro Hattori, founder of Seiko. Meet the Grand Seiko Heritage Calibre 9SA5 Platinum “Wood Grain” SLGH007J.

In 1881, Hattori (only aged 21) founded Seiko and as such, the brand is now celebrating its 140th anniversary. In honour of its founder and to celebrate 140 years of continuous operations, the brand is releasing several new models today, including this superb limited edition that focuses once again on nature, innovation and luxurious materials – classic themes for Grand Seiko.

Visually, the new Grand Seiko Heritage Calibre 9SA5 Platinum SLGH007J is sharing a lot with its steel predecessors, the SLGH003 and SLGH005. As such, it comes in the same case with the design codes introduced last year. 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.

In the same vein, the case retains its 40mm in diameter for a relatively reasonable thickness of 11.7mm. However, no more stainless steel but a case made of high-end 950 platinum. Topped by a domed sapphire crystal, it retains a certain robustness with a 100m water-resistance. To emphasize the precious and dressier side of this SLGH007J, the bracelet has been replaced by a black crocodile strap closed by a platinum three-fold clasp.

The most distinctive element of this new Heritage is its dial. Again, GS promotes Japan and local craftsmanship, with a dial inspired by the surroundings where the Grand Seiko artistic studio is located. It features a novel pattern that reflects the beauty of growing trees, with a delicate wood grain texture over a black colour. The hands and indexes, even if similar in design as the two stainless steel editions, are now made of 18k white gold. Faceted and bevelled, they still show superb execution. A framed date window sits at 3 o’clock.

Turning the watch over, the sapphire caseback reveals the innovative calibre 9SA5. It features 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.

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 is here presented with an even more appealing decoration, featuring thermally blued screws.

Availability & Price

The Grand Seiko Heritage Calibre 9SA5 Platinum “Wood Grain” dial SLGH007J will be a limited edition of 140 pieces, available from July 2021. It will be priced at EUR 60,000.

More details at www.grand-seiko.com.