If you are a fan of Seiko dive watches, you have probably heard of the Seiko Sumo. This popular model is part of the Prospex collection, which stands for professional specifications. The Seiko Sumo is a robust, reliable and good-looking dive watch that offers a great value for money. But do you know why it is called Sumo? In this article, we will reveal the secret history behind this nickname and how it relates to the design and features of this watch.
The Seiko Sumo was introduced in 2007 as a mid-range dive watch with an in-house automatic movement. It was one of the first divers to house the 6R15 caliber, which has manual winding and hacking functions. The original references were SBDC001 (black), SBDC003 (blue) and SBDC005 (orange). These models did not have the X of Prospex on their dials.
The name Sumo was not official at first, but it was chosen by enthusiasts and later adopted by Seiko itself. There are different theories about how this name came about, but they all have something to do with Japanese culture and sumo wrestling.
One theory is that Sumo refers to the wide case of the watch (45mm) in proportion to its slim strap (20mm), which gives it a muscular and hefty appearance. Another theory is that Sumo is named after the 12 o’clock marker on the dial, which looks similar to the mawashi, or underwear worn by Japanese sumo wrestlers during a fight. A third theory is that Sumo draws inspiration from the shape of the dohyō, or ring where sumo takes place. The raised bezel of the watch resembles this circular fighting zone.
Whatever the reason behind its name, there is no doubt that Seiko Sumo has become one of Seiko’s most iconic dive watches over time. It has been updated and upgraded several times since its launch, with new colors, materials and movements.
In 2019, under new references SPB101J1 (black) and SPB103J1 (green), Seiko added a sapphire crystal and a new caliber 6R35 with 70 hours of power reserve to its Sumo models. These also featured a more discreet bezel insert scale and a sunburst effect on their dials.
In 2020, under new references SPB125J1 (purple) and SPB127J1 (gray), Seiko released two limited edition models with textured dials inspired by traditional Japanese fabrics: shippo enamel for purple and hemp leaf pattern for gray.
In 2021, under new references SPB321J1 (silver) and SPB323J1 (black), Seiko upgraded its Sumo models with ceramic bezel inserts for scratch resistance and new dial patterns inspired by waves.
The Seiko Sumo is a watch that combines tradition and innovation in an attractive package. It has earned its name as one of Seiko’s most beloved dive watches among enthusiasts around the world.