2021 marks 140 years since 21-year-old Kintaro Hattori founded one of the most prestigious Japanese watch manufacturers. The Seiko Group is celebrating its anniversary by introducing plenty of commemorative collections. Milestones, in watchmaking, represent a not-to-be-missed opportunity for either the brand and watch collectors.

Again, the Prospex diving collection is among the most coveted; it all started in 2015 when Seiko revealed the collectors-ready SBDX012 Prospex MM300 50^th Anniversary with additional limited edition pieces following along the way, the pinnacle being when the manufacturer celebrated the 55^th anniversary of their professional sports watches earlier last year.

If we had to pick this year’s most wanted so far, I reckon the new Seiko Prospex Green Island trilogy is hitting the spot. The offering includes three Limited Edition models, listed as follows, left to right: SPB207J1, SLA047J1, SSC807J1, i.e., two mechanical diving watches and a solar-powered quartz one.

By taking a sneak peek at the trio, you’ll recognize Seiko has slightly upgraded the SLA and introduced the Limited Edition SLA047J1, their top diving watch if we exclude the premium-luxury LX collection.

Seiko Prospex: it’s all about the professional pedigree

We could spend hours discussing who patented the first-ever diving watch, list the historical models or rank the most attractive diving watches; let’s scrutinize products from an engineering perspective, first and foremost. Within the Prospex collection, whose moniker stands for Professional Specification, Seiko has collected timepieces featuring specifications, meeting design criteria set in ISO standards.

The truth is that Prospex is not solely synonymous with diving watches; nonetheless, professional diving is the primary source of inspiration.

Although most books keep telling the story that European-manufactured watches were chosen as favorite partners to explorers and adventurers in their endeavors to the deepest spots underwater as in their attempt to climb the highest mountains, the Prospex line up prides itself with crafting products capable of undertaking the most challenging expeditions on land, air, and sea.

Most Swiss competitors’ professional pedigree, in comparison, is often inconsistent since their products are luxury accessories rather than purpose-built timepieces. Last but not least, let’s never forget, for example, that famous adventurer Naomi Uemura was wearing a Seiko watch during his expeditions.

After proving technical prowess and outstanding diving performances, as testified by Jamstec testing three normal-production Tuna watches off the Japan’s coast, it seems the brand’s strategy is geared towards pleasing a watch enthusiast’s eyes as much as meeting the needs of professional divers who’re getting inside and out of a saturation chamber. Seiko is not the only brand to build instruments for professionals, yet the test carried out by Jamstec proves its products are a class of their own.

Each Seiko Prospex diving watch is designed, assembled, and tested according to ISO standards for diving watches. I’m afraid a few people are aware that Seiko played a significant role in drafting the norm and that the accordion or waffle strap most brands are adopting today is a Seiko‘s patent.

Whether you’re out for recreational or professional diving, making a timepiece compliant to such standards guarantees unmatched build quality and long-term durability.

In contrast, a standard consumer might somehow point out that a too rugged design and oversized case and bracelet altogether might prevent them from adding a Prospex watch to their collection. Here is why the brand is, in my opinion, unstoppably refining their timepieces from an esthetic perspective as much as they’ve so far done in both engineering and performance. The task they want to achieve is all but easy.

The design of the Seiko Prospex trilogy

Before analyzing each product reference, let’s kick off by listing what the new timepieces are sharing instead. The mainstream theme is the dark green and gold color combination and a one-off offering in terms of products per reference. The dial comes in green dark, the darkest I’ve ever seen on any Seiko‘s diver’s watch in generations, showcasing a subtle sunray finish, inspired by the Iriomote Island, located in the prefecture of Okinawa, best known as a favorite spot to professional divers, and offering vivid green vegetation.

The collection reaffirms a marketing strategy aimed at celebrating unknown Japanese landscapes; it seems the storytelling aims at making an industrially-manufactured timepiece the manifesto of Japanese culture. In the last few years, I’ve seen plenty of documentaries uncovering the long-standing tradition of Takumi master artisans, and I feel the brand gurus are eager to turn their products, and an SLA especially, into more than the sum of their mechanical components.

The green-gold color palette combo is not breaking news at Seiko; this specific pairing excluded, of course. In 2015, Seiko introduced the Seiko Sumo 50^th Anniversary, available outside Europe, and lots of product references adopting this template. I’ll pick the Seiko SPB105J1 that I own along with the Sumo 50^th Anniversary mentioned above; they’ll help us identify where the 2021 Seiko SPB207J1 is different from its forerunners.

Also, I couldn’t avoid mentioning the Seiko Prospex SPB109J1 Zimbe Limited Edition. The three new watches share a detail; they house an additional applied index or half index (SPB and SLA) located at three. It is not breaking news since Seiko introduced the latest generation SPB in the last quarter of 2020, while it makes the SLA047J1 a new take on the SLA and foresees Seiko‘s upgraded collection moving forward.

Seiko Prospex 1968 Automatic Diver’s Modern Re-interpretation SPB207J1

We’ll begin by getting our hands on the new SPB207J1, which I believe holds the most attractive value proposition and has undergone a massive overhaul from one generation to the following one. That’s why I first placed my now-discontinued SPB side by side with the new SPB and soon realized why most aficionados already nicknamed it the “Mini-MarineMaster.”

First launched as SPB187J1 towards the end of 2020, the renovated SPB pays tribute to the SLA throughout; the three-surface case side has an SLA touch and looks more premium than the outgoing model.

The new design is more compelling than ever before, starting with the small lugs’ holes machined out of a flat profile instead of finding their place across the Green Sunset’s single edge case design, where they look somehow weird and misplaced. In contrast, please forget the original SPB‘s slim case design. The SPB207J1 is thicker but bolder instead.

The bezel ring is taller and houses a new design with large grooves mimicking an SLA‘s chunky design. The detenting is crisp, far crisper than most timepieces costing twice as much; yet, the experience you get when operating a Seiko Sumo is priceless in this class of products. In this regard, I hardly understand why Seiko engineers do not standardize an experience closely connected with the product’s “touch and feel.”

The bezel incorporates a ceramic inlay, whose scaling and numerals are not centered amidst the ring, as it was on the old SPB instead. Also, the luminous dot at twelve looks too recessed in comparison. Regarding the font, I’ll standardize a single font design across the entire Prospex divers’ offering, including the likes of Turtle, Tuna, Shogun, etc. Here comes now the undisputed game-changer: the dial. It features a new design on hands, indexes, date windows as they all look and feel SLA very much.

Seiko Prospex Automatic Diver’s SLA047J1

The SLA is an icon, a legendary timepiece among professional divers. It is consistent with the original 1968 Seiko Diver‘s watch since the Seiko Prospex SLA047J1 is the only watch to adopt a one-piece case, meeting the requirements for saturation diving without adopting any helium escape valve.

The steel case is so sealed to be helium-proof. However, I must admit several Seiko and Grand Seiko achieve this performance with a standard layout and a screw-down case back. The SLA is big and bold, a true tool watch, and the commemorative collection’s talking piece.

The Japanese manufacturer boasts a long experience in engineering timepieces this exclusive; in 2015, the brand unveiled the impressive SBEX001, featuring a polished titanium one-piece case housing the glorious Hi–Beat caliber. The SBEX003 and SBEX005 with a wave pattern on the dial followed, alongside the Jamstec limited edition model.

Measuring 48,2 mm across and 19,7mm in thickness, the SBEX series is fatter and taller than an SLA. The current SLA measures 44,3mm and is 15,4mm thick.

Takumi Kishino took the SLA to the next level; the date window is smaller and sleeker, including a clean, elegant font. With the addition of a small index at three overlapping the inner flange, the dial looks and feels more premium and sophisticated.

For instance, the designer used the same approach when redesigning other Seiko Prospex models, like with the Sumo. According to some rumors, it seems a new edition of the ISO 6425 is out, and the latest design complies with the new standard, too.

The date window is visibly tinier and seamlessly integrates with the dial’s overall design. If you compare an SLA023J1 with the new SLA047J1, you end up spotting other and not-negligible details: the central seconds’ hand’s tip end is flat and not arrow-shaped any longer; the applied indexes adopt a larger ring with a uniform Lumibrite deposition. It would help if you indeed had a macro to understand how the SLA has stepped up.

The SLA047J1 comes as a 3000-piece limited edition model; we look forward to seeing the standard SLA lineup upgrade soon. Finally, the SLA has at least two additional features making this watch exclusive: it is powered by the 8L35 caliber, initially engineered for diving watches, now equipping other premium models like the 2020 King Seiko.

It also features a Zaratsu-polished case, a treatment Seiko usually reserves for premium products, like the LX. As a result, part of the SLA047J1 comes from the legendary Shizukuishi Watch Studio. With that said, I believe that the Seiko Group should further communicate what makes a Zaratsu-polished Seiko watch different from its Grand Seiko sibling.

Seiko Prospex Solar Chronograph SSC807J1

It might look odd to talk about a solar-powered quartz chronograph watch in this scenario. However, we shouldn’t forget that Prospex‘s original mission was to provide Seiko fans with rugged but reasonably priced diving watches.

This layout makes a commemorative timepiece available to a larger audience who can therefore get their hands on an ISO-certified timepiece at under 800 Euros, whose accuracy outperforms any mechanical Seiko diving watch.

Precise to +/- 15 seconds per month, Seiko‘s V192 is a solar-powered quartz movement best known for equipping the famous Prospex Sky series chronographs. Despite adopting quartz technology, the case is extra-large, measuring 44,5mm in diameter and 13,7 in thickness.

Among its pros, I’ll say it is a light watch, other than drawing its style from a Sumo. Seiko will manufacture 4000 pieces compared to the 6000 of the SPB207J1, proving the new SPB is, without a doubt, the hero of the collection.

Final thoughts

Ten years ago, I could have never imagined Seiko would develop and extend the Prospex collection so extensively. So far, its range of professional watches was so respected as restricted to a specific group of enthusiasts. The brand has improved and refined the product, inside and out, fostered brand awareness with targeted and upscale, multi-channel communication campaigns.

Seiko keeps adding a luxury sports watch feel to its proposition, improving perceived value and working hard to offer more attractive pieces, generation after generation, and at a fast pace. Try and compare an early 2000s Marine Master 300 with the latest SLA047J1; technically, the timepiece is almost unchanged but far more appealing now.

It’s time to discuss pricing and value proposition; 3300 Euros are a fair price list despite being a limited edition. I even think it’s a competitive price in the benchmark. You get an authentic ISO-certified high-end diving watch suited for saturation diving, featuring a one-piece case, a lovely detenting ceramic bezel, and zaratsu polishing all around. Seiko has not raised the standard SLA‘s price while increasing quality and detailing. I challenge myself to find anything comparable. The only letdown is it’s a big watch; the 2021 Marine Master weighs a lot, and it’s thick, making it somewhat too chunky on your wrist.

It is no coincidence that most SLA owners first replace the steel bracelet with a rubber strap or any other aftermarket option. Nonetheless, the SLA stands out as a great piece of engineering and beholder of Prospex‘s legacy. The biggest competitor to SLA is, in my opinion, its smaller counterpart, the SPB. Sporting a similarly designed case and dial and a retail price of 1400 Euros, the new SPB is expected to become the “bread and butter.”

Finally, I’d like to spend a few words on the Prospex SSC807J1; if I had to choose a diving watch, I’d barely take quartz, and vice versa, but I understand that there’s an audience of buyers who are looking for a professional diving watch on a budget. Sporting a Sumo family feeling and quite a similar price point, I would undoubtedly opt for a standard mechanical Sumo.

(Photo credit: Horbiter®)

Gaetano C @Horbiter®