Japanese, but you probably already know that. Edit: How about this one? Not an exact match, but pretty close? https://en.numista.com/catalogue/pieces9580.html or these: https://en.numista.com/catalogue/pieces14004.html https://en.numista.com/catalogue/pieces5435.html
Without having my "cheat book" nearby, I'd have to guess a 5 sen (not yen) piece. How is the metallic density? And how big is it? Nope, looks like a pre-war 10 sen piece.
Not sure about density... but it's a little bigger than a U.S. nickel, but smaller than a U.S. quarter.
On your upper picture, the cross thingy to the right is the symbol for 10. 10 sen. The leftmost mark on the other side (lower symbols) identifies the emperor.
The rest of the symbols are numerals that identify the ordinal number of that emperor's reign. I don't remember my Japanese numbers. I use the World Coins big honkin' newsprint books. Again, that cross is ten. The other two, I don't remember. Not bad. Heck, even Krause and Mishler punted on those. No KM numbers.
Japan - Taisho Era - 10 Sen - Yr. 10 (1921) Mintage: 61,870,000 Approximate Value (Fine = $0.20) - Looks VG = $0.10(?)
Hey, at least it's a CircCam! I suspected it would be in the "junkbox" pricerange, but think it's neat, all the same. File it under "cool cheapos".
Some Japanese coin info: http://www.starcityhomer.com/reading-japanese-coins.html And, if you can have the date figured out (Taisho year 10) here is a quick chart to convert too: http://www.meijigakuin.ac.jp/~watson/ref/mtsh.html This is the first 10 sen not made of silver and is a cupro-nickel alloy.
