2020 Seiko "Black Series" Sumo Limited 45mm SPB125J1

Here we have a 2020 Seiko Prospex "Black Series" Sumo Limited 45mm SPB125J1, a stealthy and imposing professional dive watch limited to just 7000 pieces. Released as part of Seiko's highly coveted, night-diving-inspired "Black Series". The commanding 45mm stainless steel case features a sleek matte-black hard coating, preserving the iconic, muscular "Sumo" silhouette defined by sweeping, aggressively contoured lines and broad, polished-bezel inner lugs. A functional lug-to-lug length of 51.5mm and a remarkably sleek case thickness of 12.5mm allow this powerful tool watch to wrap comfortably around the wrist, delivering an incredibly balanced and commanding presence. Down the right side, the signature guarded screw-down crown sits securely at 4 o'clock, ensuring a robust, ISO-certified 200-metre (20 ATM) water resistance rating. Framing the face is a 120-click unidirectional rotating bezel, fitted with a dual-toned charcoal-grey and black aluminium insert, with the first 20 minutes sharply highlighted to mirror the beam of a diver’s torch cutting through absolute darkness. A scratch-resistant, flat sapphire crystal sits flush above a deep matte black dial optimised for high-contrast, zero-reflection legibility. The dial retains the collection's classic oversized hour markers, heavily coated in a vintage-tinted Lumibrite that glows with exceptional intensity in low-light environments, complemented by a vibrant, high-vis orange minute hand that commands immediate visual focus. Positioned cleanly at 3 o'clock, a date window ensures effortless daily utility. Inside beats the upgraded, high-tier Automatic Seiko Cal. 6R35 movement, a modern mechanical masterpiece operating at 21,600 vibrations per hour (3Hz). Utilising 24 jewels and built with superior anti-magnetic properties, this dependable movement reliably replenishes a very generous 70-hour power reserve. This exclusive reference comes paired with its original 20mm integrated black silicone accordion dive strap, featuring a matching black PVD-coated tang buckle and a heavy-duty signed steel keeper. This watch is sold with its original Seiko box, swing tag and paperwork.

This watch is sold with its original Seiko box, swing tag and paperwork. The watch comes paired with its original 20mm integrated black silicone accordion dive strap, featuring a matching black PVD-coated tang buckle and a heavy-duty signed steel keeper. The watch is from Circa. 2020 and is in worn condition, but overall it is in very fair condition, as you can see from the photographs. The watch comes with our 12-Months Warranty.

A great, stealthy diver that delivers a huge amount of watch without breaking the bank. The blacked-out Sumo case works brilliantly, especially with the warm lume and that punchy orange minute hand adding just enough colour. It’s still everything you want from a proper Seiko Prospex too, robust, reliable and built to be used, with the added appeal of being part of the limited Black Series. If you want something with serious wrist presence and a slightly meaner look than your usual Seiko diver, this is a brilliant choice. Add this limited edition to your collection today!

Reference : SPB125J1 (6R35-00D0)
Movement : Automatic Seiko Cal. 6R35
Age : Circa. 2020
Year : 2020
Case Size : 45mm
Case Thickness : 12.5mm
Lug to Lug : 51.5mm
Lugs : 20mm
Condition : Pre-Owned
Box and Papers : Box & Papers
Case Material : Stainless Steel - Black
Warranty : 12-Months Warranty
The wrist model's wrist size is 7inch

Seikos history began in 1881 when Kintaro Hattori established the K. Hattori retail and repair store. In 1892, Seikosha was established to make wall clocks. 1895 saw the production of their first pocket watch. 1913 saw the launch of their first wristwatch, the Laurel. In 1924, the first Seiko was manufactured. Daini Seikosha (now Seiko Instruments Inc.) was established in 1937. Seiko was listed on the Tokyo Stock Exchange in 1949. The Suwa factory became independent and formed Suwa Seikosha Co., Ltd. (now Seiko Epson Corporation in 1959). In 1956, Seiko launched Marvel as their first true in-house-made watch; they continued to make this watch until 1959. The Seiko Lord Marvel, introduced in 1958, was Seiko's first luxury watch, predating the well-known Grand Seiko. It was designed to rival Swiss brands with a refined design and higher specifications. In 1967, Seiko launched the calibre 5740C watch movement, a significant upgrade over the earlier calibre 5740A, which beat at 18,000, and the 5740B, which beat at 19800. This movement was special because it allowed the watch to run at a high speed of 36,000 beats per hour, making it Japan's first high-frequency watch. In fact, it was only the second watch movement of its kind in the world, following one released by a Swiss brand just a few months earlier. Japan’s first chronograph watch was introduced for the 1964 Tokyo Olympics; it was called the Seiko Crown Chronograph monopusher. Not stopping there, Seiko launched Japan's first true divers' watch, the Seiko Diver’s 150M, fitted with the automatic Calibre 6217, which was later given the nickname “62MAS” by collectors. King Seiko and Grand Seiko emerged as prominent lines within the Seiko brand, with King Seiko making its debut in 1961 as a distinguished luxury watch collection. Grand Seiko, on the other hand, has consistently set the standard for exceptional craftsmanship and precision engineering. In 1965, Seiko introduced a groundbreaking manual-wind movement featuring 25 jewels and hacking seconds, coinciding with the launch of the second-generation KSK series, which boasted sharp, angular cases and robust, flat-ended lugs. The King Seiko KCM was introduced in 1969, featuring a chronometer-certified movement that operates at an impressive 36,000 beats per hour, along with a sleek C-shaped stainless steel case. In 1975, the King and Grand Quartz brands were introduced, built at the Suwa Seikosha and Daini Seikosha factories. In 1977, a high-end Twin Quartz Cal.92 was produced until 1979, when the 97KQ and 99KQ were introduced. The final 1981 King Quartz Cal.94KQ movement remained in production until Seiko ended the King Seiko line in 1985. Despite the challenges during the Quartz crisis of the 1970s that led to the gradual shutdown of King Seiko production, Seiko made a comeback in 2022 by reintroducing the classic King Seiko collection. The company name was changed to the Seiko Corporation in 1990. Innovation at Seiko continues today with GPS Solar watches.