Seiko 6217A

Probable

The caliber of the 62MAS. Neither hacks nor hand-winds, which is correct and is a period characteristic rather than a fault — Seiko automatics of the mid-1960s generally did neither.

Specifications

Movement manufacturer: Seiko
Production: 1964–1968
Frequency: 18,000 vph (2.50 Hz)
Jewels: 17
Winding: automatic
Complications: Date

Architecture

Automatic with a date, from the caliber family Seiko used for its first dive watch.

Authentication notes

MovementProbable
No hacking and no hand-winding is correct here
The seconds hand will not stop when the crown is pulled, and turning the crown will not wind the mainspring. Both are expected. A 62MAS-cased watch whose movement does hack is not running a 6217 and should be identified before anything else is concluded.

References using this caliber

Seiko 6217-8000Factory
Prospex · 1965
Seiko 6217-8001Factory
Prospex · 1965–1968

Provenance of this record

Sources & Evidence

Primary sourceTechnical documentation

Seiko caliber technical guides and parts catalogues

Seiko Watch Corporation / Seiko Instruments

Accessed: 2026-08-18

Cited for

This referenceHigh confidence

Secondary sourceCollector research

The Seiko Guy — model and reference guides

The Seiko Guy

Accessed: 2026-08-18

Cited for

This referenceProbable

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