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Seiko · Family: Alpinist

Seiko Alpinist SPB121 — reference guide

The Seiko Alpinist SPB121 is a 39.5 mm steel mountaineering watch with the line's signature green dial and a gold-tone unidirectional bezel featuring a compass scale instead of numerals. It runs the automatic 6R35 caliber (~70h power reserve) and is rated to 200 m. Cazador does not yet have enough verified market data to publish a reliable price range for this reference. Its key differentiator: it descends from Seiko's original mountaineering watches, built for orientation on land, not diving underwater.

Specifications

Reference
SPB121
Family
Alpinist (Prospex)
Case diameter
39.5 mm
Case material
Stainless steel
Dial
Green, with luminous baton indices and hands
Bezel
Unidirectional rotating, gold/bronze-tone finish, compass scale (triangular north marker, no numerals)
Crystal
Box-type sapphire crystal [UNVERIFIED]
Movement
Seiko automatic caliber 6R35
Power reserve
Approx. 70 hours
Water resistance
200 m
Crown
Screw-down, protected
Strap/bracelet
Brown leather strap (steel bracelet variant may exist depending on market) [UNVERIFIED]
Release year
2020, tied to an Alpinist line anniversary [UNVERIFIED]

Price & trend

Insufficient data

0 of 5 price observations needed to show a reliable range

There are not yet enough verified price observations in Cazador's database for this reference (n<5). We do not publish a price range until we have a minimum of 5 verified transactions or listings.

History

The Alpinist was never conceived as a dive watch — it was built as a mountaineering tool. In the late 1950s and early 1960s, Seiko developed rugged watches meant to help climbers navigate: hence the bezel's compass scale, a single triangle marking north, rather than the 60-minute scale of a diver's bezel.

The SPB121 belongs to the revision Seiko launched within the Prospex collection, restoring proportions closer to the original: a comparatively restrained 39.5 mm case, and a green dial that has become the visual signature of the entire line. Under the hood, the leap over earlier Alpinist generations (which used the 6R15 caliber) is the 6R35, with nearly double the power reserve (~70h versus ~50h), while keeping the simplicity of a three-hand automatic with date.

Frequently asked questions

Is the Seiko Alpinist SPB121 a dive watch?

No. While it's rated to 200 m, it was designed for mountaineering: the bezel carries a compass scale (a north-indicating triangle) instead of a diver's 60-minute scale.

What's the difference between the SPB121 and the SPB119 or SPB117?

They share the same case, movement, and bezel; the main difference is dial color: the SPB121 is green, the SPB119 black, and the SPB117 cream/white.

What movement does the SPB121 use and what's its power reserve?

It runs Seiko's automatic caliber 6R35, with approximately 70 hours of power reserve — a notable upgrade over the ~50 hours of the 6R15 used in earlier Alpinist generations.

Why does the Alpinist bezel have a compass scale instead of numerals?

Because the Alpinist was born as a mountaineering watch, not a diver. The compass scale, marked with a single north-indicating triangle, helps with orientation on land using the sun and a compass.

How big is the Seiko Alpinist SPB121?

39.5 mm in diameter, a mid-size Seiko chose to bring the modern Alpinist closer to the proportions of the original models.

Does the SPB121 have a sapphire crystal?

Yes, it features a box-type sapphire crystal, an upgrade over earlier versions of the line. [UNVERIFIED: confirm exact spec by production batch].

How much does a used Seiko Alpinist SPB121 cost?

We don't yet publish a price range for this reference: our database doesn't have enough verified observations (n<5).