Seiko

Hoping to pick some brains! On a whim I acquired this, I believe a 5722B from 1965. My first GS (been eyeing up a Spring Drive for a little while and saw this whilst browsing). I’ve seen a couple of these with a black dial but they seem to be almost unive...  

the markings in Japanese on the the back say basically, "In recognition of 25 years of service at Tokyo Shibaura Electricity Company". It looks like a retirement gift, possibly especially made for the occasion, so maybe that is why the dial is black. Anyw... 

Very interesting indeed! I didn’t realise it wasn’t just “normal” for that case back.

The 57GS did not come with black dials, only the typical silver dials. Many of the GS medallions were also 14k gold, so I am unsure as to why the medallion is that dirty. The W Seiko crown is also suspect, it looks like the text is pushed up to the end of... 

I’m going to remove the case back to ensure the movement is genuine. I quite like the black dial (or would not have bought it!) and given the price I paid I wasn’t expecting it to be 100% original.

Medallion looks like that because it will almost certainly be plated tin. I tested one of these once with a heat gun. Melted away in seconds (tin melting point is under 300 degrees Celsius. 14K gold, which is indeed what the vintage medallions are made fr...