The Seiko SLA017: A Study in Discipline and Depth

Watchmaking, like any mature craft, is often most compelling when it resists the temptation to dazzle.  In 2017, Seiko marked the return of one of its most quietly influential designs — the 62MAS — with a piece that does not seek to reinterpret so much as it aims to resurrect, precisely and with conviction.  That piece is the SLA017.

The original 62MAS, introduced in 1965, occupies a foundational position in Seiko’s dive watch lineage.  It was the first Japanese dive watch made to professional specifications, a timepiece that would lay the groundwork for decades of underwater instruments.  Yet the SLA017, though faithful in silhouette, is more than a vintage reissue.  It is an essay in constraint—a modern watch that understands its own past, and allows that understanding to shape it.

Casework: A Precise Evolution

The most striking quality of the SLA017 is how little it needs to exaggerate in order to assert its presence.  The stainless steel case measures just under 40 millimeters, a nod to contemporary tastes, yet it retains the low-slung stance and blocky proportions that defined the original reference 6217-8001.  This is a watch that wears close to the wrist, as a true dive watch ought to.  But what is most arresting is not the size — it is the geometry.

The lugs are sharp and squared, their flat tops brushing out in fine concentric graining that catches light in clean, consistent arcs.  The flanks, by contrast, are mirror-polished, lending the case an unexpected elegance.  It is a duality that Seiko has mastered over the years — purpose and polish existing not in tension, but in tandem.

A slim, coin-edged bezel frames the dial with tactility and precision.  It turns with a deliberate, dampened click — each of the 120 positions aligning with certainty.  Unlike many modern bezels that command attention with glossy ceramic inserts, this one is matte, legible, and unobtrusive.  It serves the dial rather than upstaging it.

The Crown and Caseback: Familiar, Yet Refined

True to its origins, the SLA017’s crown remains unguarded and positioned at 3 o’clock.  It is large enough to grip with ease, and its ridged edges feel machined with intention rather than flourish.  The decision to forgo crown guards is one of several that reflect a commitment to historical integrity.  This was, after all, a design born not in the boardroom but in dialogue with professional divers — men who needed reliability, not ornamentation.

Around the back, the screw-down caseback carries a small engraved dolphin, a motif drawn from the original 62MAS.  There is nothing ostentatious here — no exhibition window, no golden rotor, just a quiet signpost to heritage.  The water resistance has been brought in line with modern expectations, now rated to 200 metres, achieved through subtle re-engineering of the case construction.

Dial: Restraint with Texture

The gray dial of the SLA017 shimmers with a subdued sunburst pattern that shifts depending on light and angle — never flamboyant, always composed.  The hour markers are applied and filled with LumiBrite, rendered in a colour that suggests the warmth of age without lapsing into artificial patina.  Each index is sharply defined, rectangular, and generously spaced, allowing for instant legibility.

The handset, too, is drawn from the original blueprint: broad, flat, and purposeful.  The minute hand reaches confidently into the chapter ring, while the hour hand remains stout and reserved.  A date window at three o’clock sits without ceremony, neither celebrated nor hidden — a useful detail, as it was in 1965.

Crystal, Strap, and Movement

Covering the dial is a box-shaped sapphire crystal, gently domed and treated with anti-reflective coating.  It preserves the profile of vintage acrylic while bringing the durability expected of a professional tool watch.

The watch ships with two straps: a stainless steel bracelet, solid and straightforward, and a high-quality silicone rubber strap with a waffle pattern.  The latter is a loving homage to Seiko’s mid-century tropic designs and likely the more honest pairing — it feels right on the wrist, supple yet durable, entirely in tune with the watch’s utility-first philosophy.

Powering the SLA017 is Seiko’s in-house caliber 8L35, a movement produced in the Shizuku-ishi Watch Studio in Morioka.  While undecorated, it is robust, precise, and more than capable of keeping pace with the demands placed on a modern diver.  It beats at 4 Hz, offers 50 hours of power reserve, and is built to last decades, not years.

Final Thoughts: Purpose, Not Pretense

There is a tendency, in modern watchmaking, to treat heritage as a resource to be mined — each past reference a license for nostalgia.  The SLA017 does something rarer. It treats history not as a gimmick, but as a foundation.  It does not shout about its lineage. It simply honours it, in steel and silence.

This is a watch that rewards the slow look. Its appeal grows not with spectacle, but with precision.  In the end, the SLA017 is not just a tribute to a dive watch. It is a tribute to an idea: that form should follow function, but that function, when executed with care, can become form of the highest order.