What We Know
Hajime Asaoka has been a mainstay in the world of independent watchmaking for quite some time now, operating as one of the earliest representatives of Japanese craftsmanship. But his brand, Kurono Tokyo, founded in 2019 with affordable pricing and wider releases, brought Asaoka-san to a whole new audience and has become far more widely known. He’s also partially responsible for bringing Jiro Katayama and Ōtsuka Lōtec to greater visibility. While the Kurono Tokyo brand has done time-only, calendar, GMT, and chronograph watches (the first and last are probably the best known), we’ve never seen how Asaoka-san would envision a sportier dive watch. That is, until this launch here, of the simply called “Kurono Diver’s.”
Name and apostrophe placement aside (I imagine the brand is implying the ownership of the watch is that of the diver, but I digress), the watch has a creative take on what Asaoka-san sees as the core weakness of a dive watch: the crown. Since a well-regulated automatic watch shouldn’t ever need the user to interface with the crown (so long as the watch is properly set and remains wound), then couldn’t you get rid of the crown and make the watch more water resistant? It’s an interesting idea but practically challenging. Of course, there are a number of reasons to need to change the time on a mechanical watch (accuracy over any length of time is never perfect). But the concept opens up an interesting opportunity.
Instead of a crownless watch, the Kurono Diver’s is a watch within a watch. An inner 35mm 316L stainless steel cushion case (37.4mm lug-to-lug and 9mm thick) can function as a standalone watch that looks a bit more like a 1920s style officer or dress watch. Remove it from the leather strap and place it in the dive case, and it goes from 50m of water resistance to 100m if you tension the screw-down bezel and protrusions (which sit at 12 and 6 o’clock above and below the bezel ring) by hand. Or, if you twist the bezel down with the supplied “Duoseal” tool, the water resistance increases to 300m. That dive case measures 46mm by 13.5mm with a 56.7mm lug-to-lug and a bold, red, unidirectional dive bezel.
There’s something recognizably “Kurono” about the aesthetics. The dive bezel features interesting diamond-shaped markings around the 10-minute intervals, with luminous pips at the 0:X5-minute intervals and a larger pip at 12 o’clock. According to the brand, the watch is secured inside the case to prevent rotation, but according to images, it’s not clipped into anything, more so, slotted in. Inside the watch is a Miyota 90S5 movement with a 40-hour power reserve, running at 4Hz. The dial is a stark white, with slightly vintage-hued unspecified lume. Maybe the most unusual design choice is the use of cathedral-style blued hands.
The watch will be made in limited quantities, but that total number wasn’t specified. If you’re interested in buying one, you can express your interest through the brand’s website and, in a twist, divers with recreational (or higher) certification get preference (though no guarantees). The retail price is $2,700.
What We Think
This is conceptually very interesting. I think the real innovation, of sorts, is not so much that Hajime Asaoka and his team have come up with a way to “solve” issues of water resistance presented by normal case construction. The 300m max water resistance is already eclipsed by a watch like the Doxa SUB 750T at a similar price. The goal of removing points of potential water or gas ingress into the case (rather than applying something like a helium escape valve) has been tackled in a variety of ways over the years, and even an older monobloc case like that on an Omega Ploprof does the job quite well.
The real value here is that you essentially get two watches for the price of one, and a relatively affordable price for something ingenious. The dial does a good job of covering a lot of bases, working a bit dressier with the cushion-case design of the base watch, though obviously that watch might wear a little small for some people at 35mm. The added dive case is quite large (especially lug-to-lug), but it adds versatility and still matches the dial. Not having to use the tool every time to tighten the dive housing means you can have a dressier watch, a skin-diver’s worth of dive watch, or you can go the extra mile for something more dive-worthy. I would be curious to see the watch in person to better understand how it fits inside the dive case and how the dive case is secured in general (since the bezel rotates in the same direction, both to track dives and to unlock the case).
The Basics
Brand: Kurono Tokyo
Model: Diver’s: ダイバーズ
Reference Number: CS034P
Diameter: 35mm cushion shape with 37.4mm lug-to-lug (inner watch); 46mm with 56.7mm lug-to-lug (with diving case)
Thickness: 9mm (inner watch); 13.5mm (with diving case)
Case Material: 316L high-polished stainless steel, with solid caseback
Dial Color: White
Indexes: Black printed and black printed surrounds on hour markers
Lume: Unspecified luminous material on hands and hour markers
Water Resistance: 50m without the case, 100m with the diving case hand-tensioned, 300m when the case is closed with the supplied tool
Strap/Bracelet: Calf leather (19mm tapering to 16mm for the inner watch) and rubber (24mm tapering to 22mm)
The Movement
Caliber: Miyota 90S5
Functions: Hours, minutes, central seconds
Power Reserve: 40 hours
Winding: Automatic
Frequency: 4Hz
Jewels: 24
Chronometer Certified: No
Additional Details: The watch comes with an additional tool to open and close the diving case, but can also be placed in the case and tightened by hand for 100m of water resistance.
Pricing & Availability
Price: $2,700
Availability: Applications showing interest are open until March 11, 11:59 PM (23:59) JST; One application per customer. Applications with recreational (or higher) diving certifications will be prioritized but not guaranteed. Emails will be sent to allocatees between March 13 and March 16
Limited Edition: Limited release to not be repeated, but no number is given.
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