2015 marks the 50th year that Seiko has been manufacturing dive watches. To celebrate that impressive achievement the Japanese horological giant released two limited edition pieces, one of them being the Seiko Marinemaster Professional 1,000m Diver’s Hi-Beat Limited Edition SBEX001 reference – a long name (and hence a lot of features) and nothing short of what we would expect to see to mark such an occasion. Before going into greater detail on this limited edition of 700 pieces, let’s take a brief look at what Seiko has achieved over the last half a century when it comes to evolving dive watches.

You will find a nice summary of the last 50 years of Seiko divers above, courtesy of the brand. Because that list – and those watches – are worthy of their own upcoming article, we will just mention those achievements Seiko decided to highlight: the first use of a titanium case for a diver’s watch, the invention of the accordion-style strap, the two layer case construction, the “design of dial markers and hands of unparalleled legibility,” and last but not least that – they claim – the ISO 6425 standard for dive watches was developed with Seiko’s own standard as its base.

That is a long list, and while Seiko was not among the first when it came to the creation of the earliest waterproof/dive watches – you can read more on that in our “The History Of Dive Watches” article – they sure picked up the pace soon and added a fair bit to the world of professional dive watches. Over this time, the Marinemaster and the famed “Tuna” have become iconic pieces – which, fortunately, are still very much in production today.

With that, we have arrived at the what is officially called the Seiko Marinemaster Professional 1,000M Diver’s Hi-Beat Limited Edition SBEX001. What you see directly below is the original, 1968 version, with a massive (for the time, and still more than ample for today) 300 meters of water resistance and an arguably even more impressive “10-Beat” or “Hi-Beat” movement – Seiko refers to the watch as the former and the dial displays the latter term – running at 36,000 vibrations per hour.

Whether the added 700 meters of water resistance or the past 47 years had the greater impact on the design may be up for discussion, but the similarities – or, to be more marketing-inspired about it, the shared DNA – are obvious between the two. That includes the crown placement at the 4 o’clock position, the bezel with markings for all 60 minutes throughout, the similar – albeit contemporarily fatter – font, the double 12-hour and rounded indices with gold colored frames, and my personal favorite design element: the beautifully flared case side and lugs with that sweeping curve that evokes as much sensibility as it implies strength in construction. I like how all three hands are set the exact same way on the picture of the original and the showpiece that we saw at Baselworld 2015 – that’s just that extra bit of attention to detail we have come to expect.

The case is, of course, in titanium with a “Super-hard coating” to render this lightweight and rather sensitive metal more resistant to scratches and dings. The case is Seiko’s one-piece case structure which does away with the traditional case-back – in turn, making for a more rugged case. It is 48.2mm wide and a hefty 19.7mm thick – as always, though, when it comes to watches with short lugs and clever bracelet integration, wearability remains great even on a smaller wrist. The case also affords the movement some anti-magnetic protection, 16,000 A/m (I did look it up, and that is about 200 Gauss if you wish to compare it to, say, the Rolex Milgauss or Omega’s 15,000 Gauss magnetic resistance). To be fair, Seiko also offers watches with greater magnetic resistance – but here, we are looking at an all-time great in diving, so arguably, that 200 Gauss will suffice.

Another common specification with that aforementioned 1968 Seiko 10-Beat diver is the frequency of the movement inside the Seiko Marinemaster Professional 1,000M Diver’s Hi-Beat Limited Edition SBEX001. The Caliber 8L55 runs at 36,000 vibrations per hour or 10 beats per second. That is a seldom seen feat that, all other factors being equal, should provide greater timekeeping accuracy and a more smoothly sweeping central seconds hand – if that is your thing. The movement shares a lot with Grand Seiko Hi-Beat movements but is not as elaborately decorated as those, keeping the cost and hence the price down. Power reserve is 55 hours, a solid 2 days from a hi-beat movement – again, impressive stuff, especially at a time when we are still seeing some brands debuting new (and slower) movements with a mere 40 hours worth of go-juice.

One spot – and these kinds of minor details really only show themselves when a watch is seen hands-on – that I found to be a little bit off to me on the Seiko Marinemaster Professional 1,000M Diver’s Hi-Beat Limited Edition SBEX001 was the text, more specifically, the font selection on the dial. From the six lines of larger text on the dial there are four different fonts, one for the Seiko logo – which is a given, of course – one for both the Automatic and Marinemaster words, another for Hi-Beat (that, in fact, looks a bit different to the one used for the Professional), and a fourth one for the 1000m (with the little “m,” again, being arguably a bit redundant and certainly somewhat out of place). The counterpoint is that this wider selection of fonts adds a bit of welcome visual variety to the dial.

What I love about Seiko, though, is not only that you have to look at it so close to find something you may or may not like, entirely, but also that something inside of me is telling me they did think this font thing not a result of negligence, but through design decisions. As such, it is a very subjective detail and one that I’m sure will be to the liking of many.

I have kept for last what possibly is the most astounding detail of the Seiko Marinemaster Professional 1,000M Diver’s Hi-Beat Limited Edition SBEX001 (and most all other high-end Seiko divers): the lume. As always, the picture above has not been enhanced in any way: the quality, brightness and evenness of the lume is indeed a sight to be seen. Seiko uses its own luminescent solution called Lumibrite – it is indeed staggeringly powerful and is a refreshing sight after the much more ubiquitous variants of SuperLuminova.

Limited to just 700 pieces, the Seiko Marinemaster Professional 1,000M Diver’s Hi-Beat Limited Edition SBEX001, marking the 50th anniversary of Seiko dive watches, will be priced at 6,400 Euros or about $6,850. seikowatches.com