Seiko Prospex Alpinist Ref. SBDC091 / SPB121 (Commonly known as the Green Alpinist, though this variant features a black dial)
Field Watch / Compass Watch with Complications · Seiko (Seiko Group Corporation), positioned in the affordable luxury and enthusiast tier with a legendary reputation for robust mechanical movements and value
Period: Modern Luxury / Neo-Vintage Heritage (2010s-Present)
Type
Field Watch / Compass Watch with Complications
Brand
Seiko (Seiko Group Corporation), positioned in the affordable luxury and enthusiast tier with a legendary reputation for robust mechanical movements and value
Movement
Automatic, Seiko Caliber 6R35, operating at 21,600 vph (3 Hz), featuring a generous 70-hour power reserve and 24 jewels
Dimensions
Case diameter: 39.5 mm, Case thickness: 13.2 mm, Lug-to-lug distance: 46.4 mm, Lug width: 20 mm
Description
This Seiko Alpinist is a modern evolution of Seiko's legendary mountain-conquering tool watches. Combining the rugged durability of a field watch with the distinctive aesthetic of an internal compass bezel and a striking black dial, it strikes a rare balance between refined dress-casual wear and outdoor utility. The polished and brushed stainless steel case offers a commanding wrist presence despite its modest 39.5mm diameter, while the upgraded 6R35 automatic movement provides a weekend-proof 70-hour power reserve.
Key Features
Dual crown layout with an internal rotating compass bezel, distinctive triangular indices, magnified date display at 3 o'clock, and the upgraded 70-hour 6R35 automatic movement
Dial Description
Matte black dial featuring applied triangular and Arabic numeral indices with faux-patina vintage luminous fill, dauphine-style hour and minute hands with luminescent material, a signature lollipop seconds hand with an ornate counterweight, a magnified date window at 3 o'clock with a Cyclops lens, and an inner rotating compass bezel manipulated via the crown at 4 o'clock
Case Material
Stainless steel 316L with a combination of high-polished bezel/accents and brushed/satin-finished case tops and flanks
Crystal Type
Sapphire crystal with anti-reflective coating on the inner surface and an external cyclops magnifier over the date window
Bezel Details
Fixed smooth polished stainless steel outer bezel framing the crystal, paired with an internal rotating compass bezel displaying cardinal directions and degrees
Crown & Pushers
Dual screw-down crowns: the main crown at 3 o'clock for time and date setting with an 'S' logo, and a secondary crown at 4 o'clock for operating the internal rotating compass bezel
Bracelet or Strap
Stainless steel oyster-style bracelet with brushed outer links and polished center links, secured with a folding deployment clasp and push-button release
Caseback Details
Screw-down solid stainless steel caseback featuring the iconic Seiko tsunami logo and standard technical specifications engravings
Movement Type
Automatic, Seiko Caliber 6R35, operating at 21,600 vph (3 Hz), featuring a generous 70-hour power reserve and 24 jewels
Water Resistance
200 meters (20 BAR / 660 feet), suitable for swimming, recreational scuba diving, and water sports, though not rated for saturation diving
Origin & Provenance
Japanese manufacture, with production utilizing Seiko's in-house movements and manufacturing facilities
Age Estimate
Modern production, circa 2020-present
Cultural Significance
Representing the pinnacle of accessible Japanese tool watch design, the Alpinist series bridges the gap between rugged utility and everyday elegance, cementing Seiko's reputation for producing enthusiast-beloved classics that rival Swiss counterparts.
Condition Notes
Mint condition, unworn with factory protective plastic wrapping intact on the bracelet links and clasp. No scratches, dings, or signs of wear.
Value Estimate
Estimated retail market value ranges from $725 to $850 USD, depending on regional pricing, availability, and whether purchased via authorized dealers or the secondary market.
Care & Maintenance
Recommended mechanical service interval of 5 to 7 years. Ensure both crowns are fully screwed down before exposing the watch to moisture. Clean the stainless steel bracelet periodically with mild soap and warm water using a soft brush.
Similar Watches
Seiko Alpinist SPB121 (Green Dial), Seiko Presage Cocktail Time, Hamilton Khaki Field Automatic, Tissot Gentleman Powermatic 80
Interesting Facts
The Seiko Alpinist lineage dates back to 1959, originally designed for Japanese mountain climbers (Yama-otoko). It has since cultivated a cult following globally, becoming one of the most celebrated mid-range mechanical watches in horological history.