Seiko Diver’s 55th Anniversary, the 1968 “Hi-Beat” Re-Creation SLA039J1

A couple of weeks ago, we took a close look at the 1965 “62MAS” Re-Creation SLA037J1, a watch that was inspired by the mother of all Seiko diving instruments and part of the trilogy launched by the brand to celebrate the 55th anniversary of its involvement in aquatic territories. So, talking trilogy, it is time to look at the second watch that has been introduced, once again “in the metal” (and frankly, there’s a lot of metal to see…) Inspired by another iconic model, the 1968 “Hi-Beat” Diver, let’s give the Seiko Prospex SLA039J1 some hands-on time.

This trilogy of watches, as explained when we reviewed the 62MAS recreation, does not comprise proper new models but instead updates existing – and desirable – limited editions. The SLA037 is a variation of the SLA017 launched in 2017. The watch we’ll be looking at today is a declination of the already existing SLA025 presented in 2018. And like its counterpart, it is a modern re-creation of a legendary diver’s, which needs to be first introduced.

the 1968 Seiko Diver 300m hi-beat Ref. 6159-7001

If the 62MAS is considered important as being the first professional dive watch by Seiko, its successor is equally important, as it is the one that has the most influence on the design of all subsequent collections. Indeed, the 62MAS is slightly “apart” as it didn’t show yet all the signature design cues that we now see in Seiko diver’s watches. The Hi-Beat Ref. 6159-7001, on the other hand, feels far more familiar and allows understanding where most of Seiko’s design comes from.

Only 3 years after its inaugural professionally-specified diving instrument, Seiko presented its successor. But it wasn’t just an update. The work done by the brand was far deeper than just improving some areas of the watch. The 6159-7001 (and the 6215-7000, a visually almost identical watch with equal specs but no hi-beat movement) was entirely new, whether for the design, the overall resistance, the architecture or the movement.

The case of the 1968 Diver 300m Hi-Beat sets apart with its monobloc construction (eliminating any pressure points on the case) and its screw-down crown positioned at 4 o’clock – a signature feature of most Seiko’s dive watches. The case was now 300m water-resistant (vs. 150m for the 62MAS) and, as such, on par if not superior to the Swiss competition. With its 44mm diameter and 14mm height, it must have been one of the largest watches on the market at the end of the 1960s, and by that totally assuming its professional vocation. Regarding the shape of the watch, with its sharp angles and flat surfaces, it clearly set the tone for the decades to come.

The main update was not visible yet, but hidden inside the case; the calibre 6159, an automatic movement with 25 jewels… And mainly, a high frequency of 5Hz or 36,000 vibrations per hour. Rare even by modern standards, this hi-beat movement was certainly quite innovative back in the late-1960s. It was, back then, the first hi-beat diver’s watch on the market.

An interesting fact about this watch: it was used successfully by the first person from Japan to climb Mt. Everest, on the wrist pf Naomi Uemura. As such, it performed both below and far above sea level.

The 1968 Re-Creation SLA039J1

Visually and technically, the new SLA039J1 doesn’t evolve much compared to its 2018 predecessor, the SLA025. Colours apart, it remains almost identical on all points. Yet, it is still a pleasure to see this watch into the wild, and it still impresses.

Looking at the overall design, there’s no doubt on both the filiation with the 1968 model and on the vocation of this watch. It is a true professionally-oriented diver’s instrument, sharp, rugged, massive… It feels conceived for a mission and it feels like it when strapped around the wrist.

No need to hide the truth, the specs sheet talks for itself; this 1968 Hi-Beat Re-Creation is a large, hefty watch. At 44.8mm in diameter, with a 15.7mm height and over 51mm lug-to-lug, it is not going to fly under the radar. The case retains the angular shapes of its predecessor and is equally finished: circular brushed surfaces on the flat areas, polished casebands. The crown, as you’d imagine, is still positioned at 4 o’clock.

Even though a modernized version of the reference 6159-7001, Seiko remains faithful to the monobloc construction, with a case that opens through the caseback – the movement is inserted into the case from the dial side. This creates a very rigid and well-protected house for the movement but also a feeling of having an ingot, which in this context is far from unpleasant. With this in mind, you could imagine that the watch is uncomfortable on the wrist but its specific shape provides grip and balance. A large watch for sure but a watch that fits securely on the wrist.

The case is topped by a classic uni-directional bezel with a glossy metallic black insert with a 60-minute scale and a dual-curved sapphire crystal with anti-reflective coating on the inner surface. An interesting fact about the case is that it is made of “Ever-Brilliant Steel”, which is certainly comparable to 904L stainless steel. It provides better resistance to corrosion as well as more brilliance and a whiter hue. Combine this with the Zaratsu-polished surfaces and it results in a superbly finished case.

The main update on this SLA0391J compared to the SLA025 concerns the dial, which is here presented in a blue-grey sunray-brushed tone – a colour that echoes ocean depths. In addition to that, the indexes and hands are now silver-coloured (no more gilded). These colder hues provide a more modern and more technical style to this watch. All the elements of the dial are greatly executed, with bevelled hands that could easily be compared to those found in a Grand Seiko watch. The indexes and the date window frame are equally precise in their execution.

Inside its case, the 1968 Re-Creation SLA039J1 embarks the same movement as the SLA025, meaning an automatic and high-frequency engine based on the Grand Seiko Calibre 9S85. Mechanically identical to its GS counterpart, it was developed specifically for top-tier Seiko dive watches. The gear train, kinetic chain, winding system and regulating organ are the same, so is the number of jewels, the 5Hz frequency (36,000 vibrations/hour) and the 55-hour power reserve. It also retains high-tech features, such as a “Spron 610” alloy (for the hairspring) and parts manufactured by MEMS technology (escape wheel and pallet forks).

Compared to the Grand Seiko version, the differences are mostly on the decoration of the plates and bridges – even though the 8L55 is already pretty well decorated – and how the movement is adjusted. Seiko announces a +15/-10 seconds/day accuracy (compared to +5/-3 s/d for Grand Seiko), which is known to be on the pessimistic side of things.

The SLA039J1 is delivered on a matte blue silicone strap with “waffle-like” design, to remain historically relevant. It is closed by a steel pin buckle and held in place by an engraved steel holder.

Thoughts, price & Availability

When I reviewed the SLA025 back in 2018, I remember writing that it “should be seen as the über-Prospex or a wannabe Grand Seiko!” This clearly didn’t change with the 2020 version, which once again has more in common with a Grand Seiko watch than with a Samurai or a Turtle. The overall quality is impressive and so is the movement that is inside this monobloc case. This SLA039J1 is a demonstration of Seiko’s savoir-faire in high-end dive watches… which reflects in the price.

The Seiko Prospex Diver’s 55th Anniversary 1968 Re-Creation SLA039J1 is a limited edition of 1,100 pieces, which will be available as of August 2020. It will be priced at EUR 7,000. It will also be included in a special commemorative box with all three re-creations with additional black straps, which will be available in May 2020. Just 100 sets will be released.

More details at www.seikowatches.com.