The Seiko Prospex SLA023J1 Marine Master Blue watch hands-on

28 October 2019 | Seiko , Diving Watches

It is a common belief that any professional diving watch designed for saturation diving should have a helium escape valve. Also, the story goes that a single-piece steel case appeared just during the 70s, to be after that abandoned by all watch manufacturers. Finally, and this is the most bizarre if not old-fashioned, it is widely accepted that a Japanese diving watch is a perfect companion during the toughest diving session, but too professional looking and hard-to-wear as an everyday timepiece.

The Seiko Marine Master, and the 2019 edition especially, is proof positive that the above sentences are just general belief: widely considered as a pillar of the Seiko Prospex collection ever since, it is the biggest brother to watches like the Seiko Prospex Dawn Gray and the Seiko Prospex SPB053J1, following the likes of its noblest Grand Seiko siblings (and the Hi-Beat Prospex too). It is no doubt one of the most respected Seiko professional diving watches so far, and one of those that any PADI certified diver would unquestionably wear as a mechanical back-up device to the best digital equipment available.

From a technical standpoint, it gives the term "water and helium tightness" a whole new meaning: its sturdy case was conceived as a single piece of steel, such a rare choice given that its peers are often more luxury watches also designed to feature deep diving capabilities, rather than being rugged tool watches. The latest iteration of this watch, the 2019 Seiko "Marine Master" SLA023J1 Blue, has grown in style and details to become more refined than ever before.

At first glance, it is clear that Seiko's product managers aimed at refining a big, bold looking product, making it more modern, and on par with its competitors (from a touch-and-feel point of view). It is now geared towards a broader audience: the grooved rotating bezel showcases a ceramic inlay (it first appeared on the black Seiko SLA021J1), an option that Seiko has adopted later than anyone else in the industry, along with a thick sapphire crystal (sporting an anti-glare treatment on the inside, only) that has replaced the Seiko-patented Hardlex glass.

A Hardlex-made glass guarantees low replacement costs (thus positively affecting the retail price too), but is obsolete when taking into account the new Marine Master positioning. The Seiko Marine Master "2.0" first appeared in 2018 as a Limited Edition in Green, that sold like hotcakes without ever hitting the stores around the world in most cases (they almost all sold during Baselworld), and this blue variation is expected to replicate that success, without being limited in time and quantities.

Regarding the blue: it is matte blue, on the bezel, mated to a bright palette, on the dial. My feeling is that the brand's marketing gurus wanted to mitigate that rough-looking attitude, that is a Marine Master's hallmark, when making the SLA023J1, to turn the formula into something more stylish and premium instead. Nonetheless, it is quite an impressive watch: at 44,3mm across, it sports an outrageous 15,4mm thickness. It is something you have to familiarize with and accept when buying a 300m waterproof timepiece sealed to such an extent that no particle of helium would be ever allowed to enter the case.

It shares the same one-piece architecture with a Seiko Prospex 1968 Automatic Diver’s Re-creation Limited Edition SLA025, for example, but is older from an engineering perspective, and that proves why the Marine Master is thicker than its vintage-inspired counterpart. However, its bold design has made it successful, and its thickness is, therefore, part of the game. If you look around for a Swiss counterpart, the only luxury brand that has ever crafted a one-piece diving watch was Omega Watches. Its proposal was the iconic Ploprof and broke cover during the seventies. No big manufacturer other than Seiko adopts today this architecture, that is expensive to craft and hard to service too, since the only way for a technician to access the 8L35 mechanical caliber (a 50-hour maximum power reserve movement with hand-wound capability) is to remove glass, hands, and dial, first, respectively.

If we take a look at the dial, from up-close, some details make a Seiko Prospex SLA023J1 stand out, and are the gold accents chosen for logos, central second hand, and markers. The gold color is a recurring theme in the Japanese tradition and is usually associated with the most prestigious Japanese watches, not just those sporting the Seiko brand logo. Also, according to Japanese culture, colors have a strong meaning, as I learned when I discovered the meaning behind the so-called "Twelve Levels" table.

As we move down to the bracelet, it is solid and well done, but I'm not too fond of the folding clasp or, else said, I would have gone for a new one that sported not the same technical solution as a Turtle PADI whose retail price is nearly six times lower. The Seiko SLA023J1 or Seiko Marine Master Blue 2019, if you like, was long-awaited by the Seiko fans, as soon as the first photos appeared on the Internet, and I have to admit that the final product is worth that wait. It perfectly fills the gap between the Hi-Beat diving watch collection and the entry-mid range products. The price has consistently grown in comparison to the outgoing model, but so have details and specifications, with a few exceptions being the folding clasp that looks too cheap to me. With that said, no other professional diving match can ever match the unbeatable combination of price, performance, build quality, and signature Marine Master style of the SLA023J1.