Rectangular shape instead of having marks for hours 3 9 and 12 it has triangles with what appear to be jewels in them.
Looking for the correct variant to match your yellow case version of a Beau Brummell

I am not finding this setup - yellow case with white dial and three diamond settings.
The BB ad above is a different case and diamonds are round.
Unknown for now.
Nice watch! I'm currently stumped. There were a lot of Beau Brummell variants and we have yet to ID them all. My gut feeling is at this point
1956 Beau Brummell - Unknown variant
Unknown for me but that is a beauty!
Michael, does your watch have swivel lugs? Looks like it might have.
Great looking watch, I'm on the Beau Brummell fence too. Between the dial color and accent shapes of the diamonds I'm leaning to Unknown. I love those calendar bands, they were ALL the rage in the day.
I cannot find a dial case match on this. Unknown for me.