In early 2020, Seiko released a special Black Edition lineup inspired by the darkness experienced at the depths of the ocean. The range includes two Sumo's (one a Japan-only chronograph) and a MM300 based off the SLA021 case (reference SBDX033). All three feature black cases, dials, chapter rings and bezels with matching black bezel inserts. I was immediately drawn to this range, and set about making my own.
I have located a supply of high quality aftermarket monobloc cases to build a homage to the great Marinemaster. The movement will be a Seiko NH35; whilst this is a lower-end offering compared to the original 8L35, it presents a reliable, affordable, proven and serviceable movement. To make my build extra unique, I chose to take inspiration from another extreme to the depths of the ocean; moon rock. Being the focal point of the build, much relies on getting this piece right. Through some comprehensive research & some good fortune, I have managed to secure a single custom made black meteorite dial in 28.5mm for the MM300 case, from a run of 30 dials in total.
As monobloc watch cases are formed from a single piece of metal, there is no opening on the back like a traditional timepiece. The theory is that less openings means less chance of water ingress; in turn leading to a more effective diving watch.
Parts: - MM300 black monobloc bare case (300m) - Domed sapphire crystal with AR - Black ceramic bezel insert - Black chapter ring - Black polished screw-down crown - Meteormaster black meteorite dial (1 of 30 made) - MM300 polished handset - Seiko NH35 automatic movement - Black silicone 20mm Barton elite dive strap with black polished buckle
The case is constructed from a single piece of stainless steel, before being coated in black. It has a plate adhered that has been etched with a unicorn to signify it's rarity.