Have had this for a long time and wondered if anybody knew what it was. Seems to be bronze and measures approx 2" in diameter. Plain on the back
Oriental bronze disc
Re: Oriental bronze disc
Assuming it pre-dates the insertion of such objects into belt buckles, perhaps something like the Robbins Company did below. Robbins did cast some nice two-sided medallions, but in this case there appears to be a half-thick coin somehow secured to the ashtray for cigars. I completed metal shop but am no expert on how they did this...presumably the hole at the back relates to the way in which they secured the coin/medal. Unless it was hollow and filled, I would guess it too has a flat back since that side would never be seen. Of course, there are many objects to which your object could have been applied as decoration. Just one possible.