Seiko SBDC line of dive watches.
With the “Sumo” Seiko marked its return to high grade, reasonably priced dive watches that came with a hacking, hand winding automatic movement. The Seiko Sumo represents a super price/performance ratio.
For a mechanical movement it keeps excellent time and is very sturdy. The fit and finish for a watch in this price point is extremely high and the quality is close to the more expensive Marine Master.
The generously-sized case is handsomely sculpted and features subtle contrasts between brushed and polished surfaces which adds to its appeal and is reminiscent of the Marine Master.
On its first release various nicknames were discussed, in the end the final name that stuck was “Sumo” due to its large and fat appearance.
Seiko Sumo Basic Specifications:
Diameter: 48.5 mm
Thickness: 14 mm
Caliber: 6R15B, 23 jewels
Water resistance: 300m