In the past few years, Seiko has been releasing fairly faithful reissues of dive watches from its back catalog. Reinterpretations of the 62MAS, Willard, and Marinemaster models have become quite popular, and are loved by the watch-collecting community. Likely in an effort to continue this trend, Seiko has reissued another lesser-known 60s dive watch, the 6105-8000. Seiko refers to it by reference number SPB313, but the community just calls it the Slim Turtle.
The Slim Turtle watch sits alongside another SPB model, the SPB143 that I reviewed previously in the Seiko Prospex hierarchy. Its price and specs are similar to that watch, and it uses the same Seiko 6R35 movement. This places it above watches from the SRP series, like the Samurai, Monster, and Safari Tuna, but it's less expensive than an SLA series like the MM300.
In truth, I often miss my SPB143, which I sold to find the unexpected purchase of a Seiko Prospex LX. It was one of my favorite watches for around $1,000 and had very few flaws. I chose to buy the SPB313 because I liked its white dial with black hands and indices, but my hope was also that the Slim Turtle could fill the shoes of the 62MAS. Was it able to? Keep reading to find out.
A matte white dial with black indices and hands always creates a bold first impression. Upon further inspection, the hands and applied markers appear to be polished metal with a black coating applied, rather than stark black like my Vostok Komandirskie 24hr. Because of this, the furnishings on the Seiko can appear gray when light is reflected off of them. This makes it look more expensive but less striking than a true black against matte white.
Wearing the Slim Turtle
As the nickname implies, the Slim Turtle shares a similar case shape to the "regular" SRP Turtle, but with reduced dimensions. At 41mm, it is about 4mm narrower, and its 12.3mm thickness is about 2mm less than the full-size version.
Besides wearing MUCH smaller than the original Turtle, the Slim Turtle also wears smaller than its dimensions indicate. Compact lugs, and a small bezel help to facilitate this. It's a very comfortable and compact watch for a 200m diver, especially on a strap (more on that later). The sides of the case are fairly slim, and a lot of the overall thickness of the watch is hidden in the bulge on the back side of the case, allowing it to be masked a bit by the wearer's wrist.
Seiko employs a number of other techniques to slim down and clean up the look of the Slim Turtle. A lack of a chapter ring means that the crystal and dial shrink down visually.
The lack of chamfers on the case, and the tightly integrated lugs also give it a cleaner, unified appearance. The crown is also deeply recessed in the case, which hides its size a bit (and provides protection).
The 313's dial seems to be the latest evolution in Seiko's figuring out how to meet the latest ISO dive requirements. The latest spec requires a lumed marker at every hour. In the past, Seiko divers would omit the lume at 3 in order to place the date in that spot. Updated versions of Seiko's divers like the SPB143 got around this by cramming a lume marker next to the date, but the 313 took a different route by moving the date completely out of the way. A 4:30 date can be divisive, but I like how Seiko made the aperture as small as possible, and also rotated the text to be oriented correctly. Because it's color-matched, it's a pretty clean way of doing it.
Another slimming effect, at least compared to the 62MAS, is the crystal dome. The SPB143 has a more pronounced arc, and a crystal that sits proud of the bezel, while the 313 has a very subtle dome, and even the highest point of the arc is still below the edge of the bezel. The result is a less dramatic distortion of the dial. Also of note, the crystal has an effective AR coating applied to the underside.
Speaking of bezels, the 120 click action of the one on the 313 will be familiar to owners of other Seiko divers. The rotation has nice friction, but the clicks are not particularly precise or distinct. It's decent, but other divers such as my Glycine or Bulova have a higher quality feel for the price.
Beyond that, a coin edge mades the bezel easy to grip and also look good. The insert is not as attractive to look at as the ceramic one on the King Turtle, but works with the understated nature of this model.
And as you'd expect, it has that killer Seiko green Lumibrite lume (accentuated here by a Luminous Elastic Strap.
As Seiko tends to do, it has limited the dial and strap combinations available on the Slim Turtle. Right now, you can only get the white SPB313 or the black with gold indices SPB315 on a bracelet. The "regular" black dial SPB317, however, only comes with a rubber strap. The bracelet models are a not-insignificant $200 more, but you're stuck if you prefer one dial color over another.
The bracelet is comfortable and looks nice if a bit uninteresting. The fully brushed 5-link design is new for Seiko and aligns well with the style of the watch. In keeping with the slim theme, Seiko has reduced the size of the deployant clasp. This makes the clasp less bulky, but also reduces the number of micro-adjust holes from three to two. Luckily, I was able to get a good fit, but I wonder if it will limit some people who are in between links.
As you might expect, I've been wearing the 313 on a number of different straps. Removing the bracelet enhances the Slim effect of this Turtle, and it works really well on a strap. Keep scrolling at the end of the article to see more looks for this watch.
As with other SPB models, the 313 uses Seikos caliber 6R35. Compared to the 4R series movements in less expensive models, Seiko adds a Spron hairspring and other upgrades, increasing power reserve from 40 to a very useful 70 hours and improving the accuracy.
Seiko uses 24 jewels in the 6R35. It beats at a slower 21,600vph, and is listed as accurate to +25 to -15 seconds per day.
Compared to the 62MAS
Compared to the SPB143 on paper, the Slim Turtle is 0.5mm wider, 1mm thinner, and 0.7mm smaller lug-to-lug. On paper, they should wear fairly similarly, but in the metal, the 313 wears much smaller. As mentioned, this is largely because the bezel sits a few mm inboard of the edges of the case. The 143 has a large bezel that overhangs its case, and long, straight lugs that give it more visual presence.
Additionally, the 313 looks much more subdued. The matte white dial looks crisp but doesn't reflect light like the sunburst dial and polished markers on the 143. The case on the 143 also has a mix of polished and brushed surfaces, while the 313 is fully brushed. The fairly standard matte black over silver aluminum bezel on the 313 also looks less interesting than the stainless steel insert on the 143 with its radial brushing and white painted numerals.
The result is that the 143 looks much more expensive than the 313. Considering that the 143 is only $100 more at MSRP, it feels like more watch for the money. On the flip side, the white dial with black markers on the 313 looks more modern and makes it a fun watch to wear. The smaller visual size will also appeal to a lot of people who didn't like the bling factor of the 143.
The fact that Seiko offers so many models in these different price ranges means that eventually, it will offer someone for everyone. Many of its divers such as the Turtle have iconic case shapes, but they can be a bit funky, or ostentatious for some people.
The 313 does lack some of the excitement of the other Seiko case shapes (possibly why Seiko has waited longer to reissue this design), but that will serve as a positive for a lot of collectors. Not everyone wants a chunky diver, and the Slim Turtle is a watch that can blend in a bit more. Choose one of the black dial models over the bright white, and it will blend in even more.
Which is your favorite SPB series Seiko diver? Do you have another watch that you prefer? Let us know in the comments!
Name: Seiko Prospex Automatic Diver's Watch Re-Interpretation
Reference Number: SPB313J1 (SBDC171)
Lug Width: 20mm
Movement: Caliber 6R35
Power Reserve: 70 hours
Water Resistance: 200m
Crystal: Curved sapphire crystal with anti-reflective coating on the inner surface
Bezel: Unidirectional, 120 clicks
Bracelet: Stainless steel with dive extension
Shop Other Straps for the Seiko Prospex Automatic Diver White "Slim Turtle":