Made To Measure Up: Grand Seiko Professional 600M Diver’s Watch, SLGA001

The world of sports watches is an interesting one for collectors to consider, especially when choosing a watch that needs to be both robust and durable. It’s not really a question of whether or not somebody is going to wear their dive watch for diving, chronograph for timing their racing car or GMT watch for exploring the worlds. It’s more a question of whether they could wear the sports watch for the aforementioned pursuits. Not many people are going to wear their dive watch down to the limit of its depth rating; but how nice to know that in fact you could if you so desired! The Sports Collection from Grand Seiko goes that one step beyond merely looking like sports watches. They are sports watches in every aspect. From the materials used for the cases, the robustness of the movements within those cases and the execution of the dials and hands. And all of this within the brand’s core principals of a unique Japanese aesthetic and simple perfection in terms of finishing and performance; what Grand Seiko refer to as the Spirit of Takumi. And there is one piece that literally takes this spirit to new depths; watery depths in fact.

Grand Seiko Sport Collection SLGA001G (Photo: Rikesh)
The Spirit of Takumi

TAKUMI is not just a watchmaker but also a craftsman and woman who respects time, pursues the nature of time and challenges the higher aim. TAKUMI is every person who takes part of every step of watchmaking including movement design, product design, parts or case production, watch assembly, product inspection and so on.

If pushed, one could break watches down into two categories – dress and sports. It’s far from an exact science, but I believe that if I had to, I could fit almost all watches into one of the two ‘boxes’. Grand Seiko allows the wearer to enjoy the best of both worlds with dress watches that have a hint of sportiness in their aesthetic and sports watches that are refined. But a true sports watch needs to be durable in its structure and Grand Seiko understand this, as its most professional dive watch demonstrates. Anybody with even a passing interest in dive watches will be familiar with the iconic silhouette of Grand Seiko’s professional dive watches with signature four o’clock positioning of the winding crown, and this configuration is very much alive in the new, Professional Diver’s 60th Anniversary Limited Edition SLGA001G.

Grand Seiko Sport Collection SLGA001G (Photo: Rikesh)

A watch that can be used by commercial saturation divers needs to be able to withstand the most demanding tests of its durability. Depth rated to an astonishing 600 metres, SLGA001G is a watch crafted from titanium that can withstand the significant pressure at such depth but is also light enough not to be cumbersome in all contexts of daily life and daily wearing. The case is true to Grand Seiko’s beautiful finishing techniques, with only two-dimensional angles that allows each watch a highly reflective quality. Grand Seiko does not use three-dimensional or curved edges, as this distorts the light and the shadows, both of which are key elements of the house’s style. SLGA001G is finished using Zaratsu polishing, which gives the lines of the case definition and clarity and the perfect harmony and interplay with the contrasting surfaces that are hairline finished using Kuroki finishing. The polyhedron shape of the case is the perfect vehicle for the interplay of light on the surfaces.

Grand Seiko Sport Collection SLGA001G (©Revolution)

A watch that a life depends on, such as a professional saturation diver, needs to be instantly legible as split-seconds can make the difference in some of the most challenging environments that exist on earth. SLGA001G has a dial that was designed for maximum legibility, thanks to oversized and contrasting hour and minute hands. The hour markers are prominent too and are clearly legible thanks to the triangle at 12 and the rectangular quarter makers; all of which are three-dimensional in construction. The hands and hour markers can be read quickly and accurately in all lighting conditions thanks to the Lumibrite material that is used. Lumibrite is an exclusive development by Seiko and is a luminous material without any radioactive elements. It can stand the test of time by shining brightly, due to its ability to efficiently store light energy and release it slowly, therefore staying brighter for longer. In line with safeguarding a diver ‘in action’, the bezel can only be turned uni-directionally and unlike other brands, each click is for 30 seconds.

2020 60th Anniversary Limited Edition Professional Diver’s 600M SLGA001 (Image: Grand Seiko)

Equally imperative is a movement that can be relied upon and Grand Seiko opted for the calibre 9RA5, based on the Spring Drive technology, for their toughest dive watch. When you are relying on your watch with your life, you don’t want to lose a second! Calibre 9R05, is a movement that is accurate to within ten seconds a month with an impressive five-day power reserve. The 9RA5 was designed by Eiichi Hiraya. The Spring Drive technology was 28 years in the making and still now, Hiraya is looking for ways to make the movement even more reliable and durable. Embodied by the Spirit of Takumi, he is bound to make the best even better. The 9RA5 features a new Spring Drive package integrated circuit (IC) that enclosed an IC in a vacuum package that controls the accuracy of the Spring Drive movement, a quartz oscillator, and the wiring that connects them. “It took a great deal of time to find the optimum structure to enclose the IC and quartz oscillator, which until now had been mounted separately, in one vacuum package. Since the vacuum package cannot be opened once it is sealed, we naturally used a quartz oscillator with stable performance that was carefully selected by ageing it for three months,” says Hiraya. This single vacuum package also overcomes the issue of temperature fluctuations due to the fact that the vacuum package encases the quartz oscillator and temperature sensor, which eliminates any differences and resulting impact on timekeeping.

Eiichi Hiraya
Eiichi Hiraya
Calibre 9R05
Calibre 9R05

In the same spirit, the calibre’s robustness was also addressed: “We reinforced the 3 o’clock/9 o’clock direction, which is where the main plate is weaker than other parts and housed all the gear trains within this structure. In doing so, we greatly enhanced its robustness. Also, the integration of the three bridges, which had previously been separate components, eliminated variations in components and assembly and also contributed to enhanced transmission efficiency. All these innovations have made Caliber 9RA5 a robust, slimmer movement with improved accuracy and I am proud of what we have achieved.”

Whether you are a Grand Seiko collector, general watch enthusiast or indeed a professional or recreational diver, you would be hard pressed to find a more capable and striking diver’s watch. And don’t just take my word for it, the SLGA001 was nominated for the GPHG Awards in the Diver’s category this year too.

Grand Seiko Sport Collection SLGA001G (Photo: Rikesh)
Grand Seiko Sport Collection SLGA001G (Photo: Rikesh)

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