Seiko 5126-8090 (Mirrored Daini logo)
The 5126-8090 is commonly called the Mirrored Daini logo.
This entry covers one 5126-8090 caseback from 1968 on which the Daini Seikosha logo is stamped mirrored, reversed left to right. The rest of the caseback reads normally for the reference. The submitter states that after researching it and asking other collectors, they concluded it was a manufacturing error at the factory rather than a deliberate variant. No second example has turned up in the sources checked for this archive, so it is recorded as a single documented piece, not a known variant. The serial in the photographs reads 850538, which under Seiko's dating scheme of the period points to May 1968. The dial, case and 5126 movement are covered on the 5126-8090 page.
| Caliber | 5126 |
|---|---|
| Years | 1968 |
| Line | Seiko 5 Sports |
| Sub-line | Mirrored Daini logo |
| Factory | Daini |
Identification
Compare the Daini logo against a standard 5126-8090 caseback. On this piece the logo is reversed left to right, and the other caseback text should read normally. Check that the reversed logo has the same stamping depth and finish as the surrounding text. A logo that looks shallower, crisper or differently finished points to later work on the caseback, not a factory error.
Authenticity
A one-off has nothing to check it against. Ask for clear, angled photographs of the caseback, and compare how deep the logo is stamped with the text around it. Confirm the caseback belongs to the watch it is on. The serial should date to the same period as the dial and the movement.
Is the mirrored Daini logo on a 5126-8090 a known variant?
Not as far as this archive can find. The submitter checked with other collectors and concluded it was a manufacturing error on this one caseback. Until a second example appears, treat it as a one-off rather than a variant to look for.
How do I date a 5126-8090 from its caseback?
Read the first two digits of the serial. The first is the last digit of the year and the second is the month, using 1 to 9 for January to September and O, N and D for October to December. This caseback reads 850538, so May 1968.
