I stumbled across this under a box flap. The box was loosely packed with misc Japanese bring-back from the GHQ era by an uncle. There weren't any other coins in the box, sorry! Orientation is correct, I think; obverse/reverse is a guess. The second pic shows what looks to me like a silver upper portion, inlaid on a brass coin. That's simply an impression...could be the whole thing is silver, the coin otherwise just being tarnished. Your opinions and observations are eagerly anticipated, folks. Thanks for lookin'!
You could start looking at this type. https://en.numista.com/catalogue/pieces88796.html Yours is worn and the character for 2 (left of obverse) doesn't look quite right. IMO I am sure others more familiar will chime in soon
I'm pretty fuzzy on these, but in the absence of dimensions/grams (and a better fund of knowledge) but it looks like it's probably a Meiji era 2 bu. Would be about 3 grams/19 mm, and they were .223 gold and .777 silver. If it's a bit bigger it could be Ansei era (24 mm, 5.62 grams). The other 2 bu have an extra era character in the upper right of the signature side/reverse/big loopy character not reminiscent the stylized plant-like crests. It could be a victim of bad environmental effects which sounds about right for how you found it. I've got a small handful of some of the 2 bu and it's one of my 'projects' to work on figuring them out better.
