Fresh off the boat is the Citizen Promaster Mechanical Diver 200M in two variants. This debut series of NB6021 models is the revival of a 45-year-old mechanical dive watch in the Japanese giant’s archives. The modern interpretation focuses on technical updates while preserving the look of the original design. The retro-inspired Promaster Mechanical Diver is crafted in Citizen’s proprietary Super Titanium, and it comes in both blue and black versions.

Citizen says it has kept the new model’s design entirely faithful to that of the 1977 Challenge Diver. Of course, not many of us can travel to the company’s museum in Tokyo to see for ourselves. Luckily, our resident vintage-collector extraordinaire Mike shared the one in his possession in this 2020 article to ease our curiosity.

A material upgrade

Compared to Mike’s vintage example, the new Promaster Mechanical Diver measures 1mm wider (on paper, at least). The 41mm titanium case is 12.3mm thick, however, making it slightly thinner than the steel original. The use of Super Titanium is certainly a quantum leap. As solid titanium that has undergone Citizen’s proprietary Duratect surface-hardening treatment, the brand calls it a “space-age” material. Not only is it five times harder and 40% lighter than stainless steel, but it is also scratch-resistant, luster-prolonging, and hypoallergenic. Rob delved a little deeper here if you’d like to read more about the brand’s over-50-year love affair with titanium.

Citizen Promaster Mechanical Dive Watch NB6021

A solid build

To be fair, one could argue that the Challenge Diver’s case construction was robust enough to forgo a material boost. To support that argument is an exhibit of a unique specimen coated with barnacles in the Citizen Museum. The staff has nicknamed it “Fujitsubo”, which means “acorn barnacles” in Japanese. Fujitsubo washed up on the Long Reef Beach in Australia and was found in 1983, still ticking away.

A retro diver

That Challenger Diver was cased in stainless steel and fitted with a bidirectional bezel with no crown guards. The fact that it survived for years submerged in the Pacific Ocean was a clear testament to its strong, water-resistant build. The new Promaster Mechanical Diver marks the comeback of that model and should appeal to lovers of vintage and retro-styled watches alike. Chances are, it may see more desk diving than underwater adventures, in which case, titanium’s lightweight quality wins for wearability.Citizen Promaster Mechanical Dive Watch NB6021

A faithful revival

Apart from the material upgrade, the Promaster Mechanical Diver 200M affords the rotating bezel with a unidirectional mechanism. To stay true to the original design, the crown remains unguarded. Everything from the knurled bezel and countdown scale to the minute markings, indexes, handset, and even classic green lume is there to replicate the retro style. And that includes the sapphire glass which has a flat top, a domed underside, and a beveled edge. All aesthetics are the same except for the text above 6 o’clock, now indicating it is made of titanium with improved ISO-compliant water resistance up to 200 meters.

A robust engine

Powering the new NB6021 Promaster Mechanical Diver series is the automatic caliber 9051. This Miyota movement operates at 28,800vph (4Hz), features hacking and hand-winding, and provides approximately 42 hours of power reserve on a full wind. In its literature, Citizen highlights the use of anti-magnetic materials for the balance spring and surrounding components. The movement can resist against smartphones or any device with a magnetic field of up to 16,000 A/m within a 1cm radius. Citizen also advertises an average daily accuracy of +20/-10 seconds when stationary.

Citizen Promaster Mechanical Dive Watch NB6021

The first series of the Promaster Mechanical Diver 200M comes in blue and black variants. The NB6021-68L blue version on a Super Titanium bracelet is priced at €749, while the NB6021-17E black version fitted with a black polyurethane strap is €649.

For more information, visit Citizen’s EU website.