THE SUMO, A MODEL BORN IN 2007

The Seiko “Sumo” is one of the many much-loved and respected dive watches that are produced by the Japanese brand. Robust, rather simple, reliable, not especially elegant but still good looking.

The Seiko Prospex Diver 200m SBDC031 was launched in 2007, as a mid-range offer, above the entry-level Turtle and Samurai and below the MarineMaster 300m. A better movement than the two affordable pieces on one side, a case with more attention to details too, but a lower water-resistance and no sapphire crystal like the MM300.

THE NEW SPB103J1, A TECHNICAL AND VISUAL UPDATE

The new Seiko Sumo – or Prospex Diver 200m SPB103J1 – isn’t a complete departure from the older model and keeps most of the attributes found on the SBDC031. Consider this new version as an update, with multiple improvements and slight visual evolutions, rather than an entirely new watch. All in all, the fundamentals are still present but the technical side has been improved, for a better owner experience.

The dial of the 2019 Seiko Sumo Prospex Diver 200m only shows some minor updates compared to the 2007 model. As you can see, the indexes and markers are almost identically shaped (including the iconic Sumo marker at 12), the date is still framed by a white line and the inscriptions are all about the same. The main difference comes from the hands, with a slender minute hand and an hour hand that now matches the “Sumo” theme, without the triangular tip. Indexes and hands are still generously filled with luminous paint.

While the previous version of the Seiko Sumo was powered by the calibre 6R15, the new 2019 Seiko SPB103J1 and SPB101J1 feature the calibre 6R35. The base remains the same, with a 3Hz frequency, a central rotor for the automatic winding, a quick-set date, and a stop-second device, however, the power reserve has been improved to a comfortable 70 hours (instead of 50 hours). The movement is hidden underneath a screwed steel caseback.