Caseback
Tsunami (wave) medallion caseback
ProbableThe stamped wave medallion used on Seiko dive casebacks from the 6105 era onward, alongside the case number and the six-character serial. It is a design element and an era marker, not a certification of anything — and because casebacks unscrew, it travels between watches freely.
Part reference
- Brand
- Seiko
- Material
- Stainless steel
- Identifying marks
- Wave relief; case number and serial stamped around it. On SKX007J examples, 'Japan A' appears beside the serial.
Documented variations
Classification
FactoryDocumented as shipped from the factory for this reference and period.PeriodNot original to this watch, but correct for its production period.ServiceFitted by the manufacturer's own service network. Not a defect.AftermarketThird-party part. Affects originality, not authenticity.ModifiedGenuine parts in a configuration the factory did not sell. Affects originality and value, not authenticity.CounterfeitDeceptive reproduction intended to pass as genuine.UnknownEvidence on file does not settle the question.Correct caseback for the reference
FactoryProbableWhole production
Case number on the back matches the watch's actual configuration and movement.
Substituted caseback from another reference
UnknownHigh confidenceWhole production
A caseback is the easiest part of a Seiko to change and the one carrying the identifying number, which makes it the standard vector for misrepresenting a reference. A 6306 caseback over a non-hacking 17-jewel movement is the canonical example. Never treat a caseback number as establishing the reference on its own.
Documented on these references
No reference fitments are documented for this part yet.
Provenance of this record
Sources & Evidence
Plus9Time — Seiko case back, case numbering and model research
Plus9Time
- Accessed
- 2026-08-18
Cited for
Last verified: Not yet reviewed