SEIKO PROSPEX SPB101J1 AUTOMATIC BLACK SUMO SAPPHIRE 3RD GEN MEN WATCH

Seiko Prospex SPB101J1 — Sumo Automatic Diver's Watch

The Seiko Prospex SPB101J1 is a black dial Sumo diver — the Sumo case shape paired with one of the most purposeful and commanding dial executions in the Prospex lineup. The black dial against the silver stainless steel case and unidirectional rotating bezel gives it an immediate authority that the lighter dial variants in the Sumo family do not share in the same way, and the oversized 12 o'clock index — the design detail that gave the Sumo its collector nickname — reads with complete clarity against the black background. Powered by the in-house 6R35 automatic calibre with hand-winding capability and a 70-hour power reserve, it delivers the full Prospex diver's specification in the Sumo's distinctive wide-body 45mm case.

The sapphire crystal protects the black dial through active daily use, and Lumibrite on the hands and hour markers ensures readability at depth and in low light. At 45mm and 12.9mm slim — with a 52.6mm lug-to-lug — the Sumo case wears with the comfortable, substantial wrist presence that has made it one of the most beloved case shapes in the Seiko Prospex family. The silver stainless steel bracelet completes a classic, high-contrast presentation.

Key Features

• Seiko 6R35 automatic movement with manual winding — self-winding with the convenience of hand-winding when needed
• Approx. 70-hour power reserve — dependable performance through an extended weekend without wearing
• Accuracy: +25/-15 seconds per day (5°C–35°C) — dependable automatic timekeeping
• Diver's 200M water resistance — built for recreational diving and water sports
• Black dial with baton markers — commanding, high-contrast Sumo execution
• Lumibrite on hands and hour markers — superior legibility in low light and underwater conditions
• Unidirectional rotating bezel — purpose-built for safe and accurate dive timing
• Sapphire crystal — premium scratch resistance and superior optical clarity
• 45mm silver stainless steel case — Sumo proportions at 12.9mm slim profile
• Screw-down crown — water integrity protection for diving use
• Date display — everyday practicality built in
• Silver stainless steel bracelet — durable, comfortable, and corrosion-resistant

Why You'll Love It

The SPB101J1 is the Sumo for the collector who wants the case shape in its most authoritative and understated expression. The black dial and silver stainless steel case is the classic diver's colourway combination — there is no ambiguity about what this watch is or what it is for. The Sumo case shape is known for its exceptional wrist comfort at 45mm: the cushion-like proportions distribute the case width across the wrist more naturally than a standard round case of the same diameter, making it one of the most comfortable 45mm dive watches available. The 6R35 calibre's 70-hour reserve handles any extended weekend, the sapphire crystal keeps the dial pristine, and the Diver's 200M rating means it is ready for the water.

About the Seiko Prospex Sumo

The "Sumo" nickname — so widely used among Seiko collectors that it functions as the model's common name — refers to the distinctive case shape first introduced in the Prospex diver lineup: wide, substantial, with a strong visual mass and an oversized 12 o'clock index that references the solidity and authority of the sumo wrestler's stance. The case shape has earned a devoted following for its combination of bold proportions and exceptional wrist comfort, and has become one of the most recognisable silhouettes in the Seiko Prospex family.

The Seiko Prospex Story

Prospex is a combination of the words "Professional" and "Specifications." Seiko Prospex timepieces are designed to be practical, reliable, and durable — built to meet the high standards required in extreme environments for sports lovers and adventure seekers alike. The story begins in 1881, when Kintaro Hattori founded a clock and watch shop in Ginza, Tokyo — the business that would become the Seiko of today. Since 1965, when Seiko created Japan's first diver's watch, the Prospex dive line has stood for underwater precision and reliability. The SPB101J1 carries that sixty-year legacy forward in the most direct and confident expression of the Sumo diver.

Backed by Seiko's official warranty. Authentic Seiko Prospex watch, sold by authorised retailer City Chain Singapore.

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