A Tiny Hour Tales reference desk
Read any Seiko — by serial, caliber & catalogue.
Decode a caseback serial, look up a movement, and trace any model through ninety years of original Seiko catalogue. Built for collectors, kept by a watch shop.
Tools
Serial Decoder
Date any Seiko from its caseback serial.
Caliber Lookup
Movement specs & production windows.
Vintage Case Code
Decode pre-1966 five-digit case codes.
Model Finder
Identify a watch from its features.
Strap Size
Lug width & strap recommendations.
Battery Estimator
Quartz battery age & change reminders.
Decode a serial in seconds
The number engraved on the caseback tells you the month and year it was made — entirely in your browser.
Where do I find these numbers?
The serial is engraved on the outside of the caseback (the metal back of the watch). The caliber is the 4-character movement code — it’s the first part of the case reference, e.g. 6309-7040, also stamped on the movement itself.
Type a serial above — the decode appears here instantly, entirely in your browser.
Ninety years of Seiko, catalogued.
A growing, searchable library drawn from 125 original Seiko catalogues — search by year, model reference or caliber.
Explore the catalogue
Found the one you’ve been chasing?
Curated vintage & modern Seiko, serviced and ready to wear.