The Introduction
Seiko Prospex has become almost synonymous with Japanese diving watches ever since its release (though not yet named Prospex) in 1965. Since then, Seiko has emerged as one of the absolute favorite brands among dive watch enthusiasts, thanks to their tough construction and innovative designs. This SBEX001 is the culmination of 50 years of Seiko dive watch development and is, without a doubt, the most sophisticated mechanical dive watch Seiko has ever produced.
This 50th anniversary model, the Hi-Beat, is not actually a throwback to the original 1965, but to the 1968 incarnation, the first to feature a Hi-Beat movement, by which I mean one that beat 10 times per second. Like today's watch, that 6159-7001 used a Grand Seiko automatic that beat at an even-now impressive 36,000 BPH. There are other similarities between the 6159-7001 and the SBEX001 as well. The gold hands and accents, the shape of the hour markers, the gold writing and the red tipped seconds hand, to name a few. Side by side, the resemblance is very clear.
But they're not entirely the same. Some dial and bezel accents, the size, and of course the more advanced movement account for much of the difference, but also the vastly increased water resistance, from 300 meters to an over-the-top 1000 in today's SBEX001.
The Dial
The dial is about as bold as you're going to get from a vintage-inspired model. The watch itself is very large, but so are all the elements of the face. The hour markers, the hands, even the SEIKO writing at 12:00.
Take a look at these massive hour markers, for instance, another element inspired by the original. Whether or not the powerful Lumibrite is glowing, they offer excellent contrast against the dark dial.
Because the dial is so recessed from the bezel, the hour markers occasionally give the owner a hint at their intensity even in ordinary lighting.
For better or worse, even the Seiko writing is supersized here. I don't mind it at all, actually, since it's not accompanied by an applied logo, in keeping with the original model. I like the texture of the gold writing as well. Although this dial doesn't lack for writing, it's worth mentioning that unlike its Grand Seiko counterparts, Seiko is thankfully only referenced a single time.
One fairly significant departure from the inspiration is the date placement. The original had a more conventional date at 3:00 with gold frame. The SBEX001's approach, however, is between 4 and 5, a common design choice in dive watches because it doesn't require the omission of a luminous 3:00 marker. The frame was almost certainly dropped for space reasons.
Being a Seiko diver, you already know it's going to have great lume, but I haven't seen anything like this before. I'd like to do another multi-dive watch comparison, but just eyeballing it, this is the most powerful lume I've ever seen. This photo was taken in a well lit area, by the way, only camera settings brought the brightness down. Aside from resizing and the watermark, it has not been edited in any way.
The hands are quite reminiscent of the original 6159-7001 as well, thanks to their gold trim, but there are several differences. The new hands are much pointier and angular. The design of the minute and hour hands is somewhat opposite one another as the direction they taper is reversed-the hour hand gets wider towards the tip while the minute hand gets narrower. The seconds hand still retains a red accent at the tip, but the lume is now entirely of the "lollipop" variety on the counterbalance.
The dial is a mix of new and old, but mostly old-as I wrote earlier, the resemblance to the 6159-7001 is unmistakable. It's been tastefully updated but it's still a great homage to the first Hi-Beat Seiko diver.
The Case
The case is certainly one of the more noticeable aspects of the watch. I won't beat around the bush-it's a very large watch. At 48.2mm, it's already quite big, but it's really the 19.7mm thickness that's most visually impressive. I will say that it does wear very well, thanks to the short lugs, but there's no confusing this for something small and discreet-Seiko was making a hardcore diving watch here and there were clearly no compromises allowed.
The feeling of size is diminished, however, thanks to its all titanium design and bracelet. Even still, I wouldn't call it a light watch-I'd say it feels about the weight of an ordinary (but much smaller) steel watch, which is a good thing in my opinion. The titanium has a super hard coating, which is definitely something its owners are going to appreciate.
The crown does, of course, screw down for an amazing 1000 meter water resistance. The more astute among you will notice that there is no helium release valve, a common feature of watches with super high water resistance ratings. This is because Seiko developed a specialized gasket in 1975, known as the L-shaped gasket, that rendered them unnecessary.
The case is of the monocoque variety insofar as there is no discrete case back. The whole case is a single piece of titanium. This does wonders for structural integrity. The wave motif is emblazoned on the back, although it's surprisingly subtle for such an in your face kind of watch.
The unidirectional rotating bezel was a bit of a surprise. Seiko always has great bezels, but I was expecting this one to require a lot of force to move, perhaps due to the watch's size and hardcore appeal. In fact, while it's just as buttery smooth as any other high-end Seiko, it takes less effort than most. It's not loose by any means, but you're not going to develop any calluses turning it either. Stylistically it looks great although there are a couple of differences from the original model. For instance, the small pip at 12:00 is now a huge triangle and the gold writing in the bezel is much more subtle, both improvements in my opinion.
The Movement
Like some other elite Marinemasters, a Grand Seiko movement is used, or rather, a version of a Grand Seiko calibre. However, other models that have received a Grand Seiko-derived movement were using a 9S55, a last gen, regular-frequency movement. This is the first modern Prospex to receive a GS Hi-Beat movement period.
Just a note, however: because there are no photos of the 8L55 in this watch, I will be using photos of a very similar movement, the 9S85 SPECIAL, which is mechanically identical to this 8L55.
So what is the 8L55? Basically, it's the non-Grand Seiko version of Grand Seiko's most impressive movement, the 9S85 Hi-Beat. The defining characteristics of the movement, namely beating at 10 beats per second, as well as all the other technology you love, like SPRON alloy springs and MEMS manufacturing tech, as well as a skeletonized pallet fork and escape wheel, are still present in the 8L55.
Like the 9S85, it still has a 55 hour power reserve as well, one of the longest reserves of any high frequency watch.
So is the 8L55 just another name for a 9S85? Well, not exactly. The movement is undecorated, so if you were to remove it from your new SBEX001 (not an easy thing to do thanks to that one-piece case), it would not be as pretty as a 9S85. More important, however, is the fact that it's unadjusted. This was true of the 8L35 as well, the GS 9S55 derived Marinemaster movement. One of the key features to any Grand Seiko mechanical movement is the extremely precise adjustment.
Lacking this, we can expect the 8L55 to be somewhat less accurate despite being functionally identical. You could, in theory anyway, take an 8L55 and adjust it to the same accuracy as any 9S85 if you really wanted to. Grand Seiko jealously guards their mechanical and quartz movements (as opposed to their 9R spring drives, which you can find throughout high-end Seiko) so I imagine that this was a necessary compromise for Prospex to have access to the 9S85. Adjusted or not, on a technological level, it is one of the most advanced movements ever put in a diver.
The Video
Check out our high-definition video of the SBEX001 here!
The Conclusion
So what is the SBEX001? An homage to a classic diver? A celebration of 50 years of Prospex? Well, yes, but it's also more than just a symbol: it's a great diving watch.
The SBEX001 is very much a high-end Seiko in execution. Incredible attention to detail and to tradition, both in terms of movement and design. The 8L55 is probably the greatest movement, aside from perhaps the 5R spring drive, to grace a Prospex and the watch just looks terrific.
Yet, despite its greatness, it isn't for everyone. This is a watch for the connoisseur. The true Seiko diehard, the collector that appreciates the history and the advanced movement. And he's also going to have to like big watches. Not that it matters too much as there are only 700 made, so there's a pretty decent chance that by the time you read this they'll all be gone, particularly given the immense popularity the watch gained at its Basel release.
As for me, I think it's the best Prospex ever made. I really loved the recent spring drive SBDB009 as well, but I suppose my personal preferences lean towards mechanical movements generally, and I daily wear a 9S85 so I can probably be counted as biased towards Hi-Beats. It's a great watch and I hope to see the 8L55 making an appearance in future Prospexes as well. If you are fortunate enough to own an SBEX001, you have something quite unique on your hands as, at the time of this writing, it's the only 8L55 movement in the world.
