Hi everyone,

I recently picked up a Seiko 7C43-6010 Professional 200m Diver straight from Kamakura, Japan—and I’ve fallen completely in love with it.

But here’s the twist: it’s not just another well-worn diver. This one came with some really unusual caseback and service markings that have me wondering if it was institutionally issued—possibly military, maritime, or industrial.

Here’s what makes it weird (and wonderful):

Stamped on the caseback:

• B0305
• B0510
• B0910

…

Stamped, Scarred, and Possibly Issued – Meet My 7C43-6010 ‘Kamakura Diver