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Seiko Alpinist SPB531: EU-Exclusive Blue Edition with 6R35 Movement

Europe-Exclusive Blue Alpinist

Seiko’s new Alpinist SPB531 is a limited edition exclusively for Europe, capped at 3,000 pieces. The watch retains the original field‑watch spirit with a 39.5 mm stainless‑steel case and dual‑crown internal compass bezel but updates the look with a deep midnight‑blue dial finished with vertical brushing and a copper‑coloured seconds hand. Applied numerals and markers add depth while cathedral hands deliver vintage charm. The case remains robust with 200‑metre water resistance and a sapphire crystal with date magnifier. Each watch is delivered with two straps — a blue calfskin leather strap and a navy nylon strap — in a special edition box.

Wearability & Case Details

A case measuring 39.5 mm across, 13.2 mm thick and 46.4 mm from lug to lug makes the SPB531 wearable on a wide range of wrists. Seiko finishes the stainless‑steel case with alternating brushed and polished surfaces, while a pair of screw‑down crowns at 3 and 4 o’clock control time/date and the internal compass bezel. The watch carries a domed sapphire crystal with anti‑reflective coating and a magnifier over the date, plus a screw‑down display caseback. Despite its compact dimensions, the watch is rated to 200 meters, reflecting its tool‑watch heritage.

Dial and Movement Details

The midnight-blue dial is vertically brushed and features applied numerals at even hours and triangular markers at the odds. A copper-coloured seconds hand contrasts nicely with the dark background and matches the vintage-style cathedral hour and minute hands, while a date window with magnifier sits at three o’clock. Powering the watch is Seiko’s calibre 6R35 — a robust automatic movement with 24 jewels, 21,600 vibrations per hour and a healthy 70-hour power reserve. The movement hacks and hand-winds, and is visible through a screw-down display back. Two screw-down crowns operate the time-and-date and the internal compass bezel.

Packaging, Availability & Pricing

Seiko packages the Night Sky Alpinist in a special edition box that includes both a blue calfskin strap and a navy nylon strap with matching pin buckle, letting wearers switch between dress and sporty looks. Only 3,000 pieces will be produced for the European market, making this a highly limited run. Pricing is expected to sit around €930 (approximately £780), and the watch will be available through Seiko boutiques and authorised dealers across Europe starting late summer 2025. As always, final retail price and availability may vary by country.

Tech Specs

The Basics

Brand Seiko
Model Prospex Alpinist “Night Sky”
Reference SPB531 / SPB531J1
Limited Edition 3,000 pieces, Europe exclusive
Case Stainless steel
Diameter 39.5 mm
Thickness 13.2 mm
Lug-to-lug 46.4 mm
Crystal Domed sapphire with date magnifier & internal AR
Bezel Internal rotating compass (twin-crown)
Water Resistance 200 m
Dial Midnight-blue, vertical brushing, applied numerals & markers, cathedral hands with copper seconds
Straps Blue calfskin & navy nylon (special edition box)

The Movement

Caliber Seiko 6R35
Type Automatic, hand-winding & hacking
Frequency 21,600 vph (3 Hz)
Power Reserve Approx. 70 hours
Jewels 24
Functions Hours, minutes, central seconds, date

Price & Availability

Price Approx. €930 (~£780)
Availability Europe only; deliveries from late summer 2025
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