Need Help Identifying Vintage Omega Seamaster for (presumably) Japanese Market

Hi everyone,

First time poster here, but long time watch collector and admirer. I've developed a particular taste for vintage Omegas.

Anyways, I recently purchased a vintage Seamaster from an eBay seller in Japan. It's obviously for the Japanese market since half the day characters/letters are in Japanese. I'll be attaching a picture of the watch for view, but I'll give some additional details.

Color: yellow gold capped
Diameter: 35.5mm w/o the crown
Lug-to-lug length: about 40mm
Lug width: 17mm, but as you can seem, the bracelet flares out by the lugs
Serial number: 53658599
Year: unknown
Other notes: Listing said JapanX950, but I don't know if that means anything.
Listing from dealer: https://everywatch.com/omega/seamaster/watch-12251166 (and no, I didn't pay that price, if you're wondering)

I guess you could say it sort of looks like a modern Constellation and the closest vintage it seems to resemble is a DeVille 166.051, but the latter is smaller.

Curious what the reference number is and maybe a little more about the watch, the year, like history, variants, etc. I don't think I've ever seen anything like it.

Thanks everyone.

Appreciate the reply! I just looked up the reference number you gave and that is, indeed, the watch. I didn't know the year since it wasn't provided and the seller didn't know either. Doesn't seem to be a lot of these around!