I have found an identical coin though on ebay, the exactly same as yours...but silver coloured. It's title read 'Large Size Coin of Japan 10,000 Yen Meiji year 8'
to CoinTalk jnb. Your item is a Chinese fantasy piece. In Meiji 8 (1875), ¥10,000 would have been worth approximately US$10,000, and in .900 silver a coin of that denomination would have had to weigh 269,568g (more than 593 av. pounds, or 7,800 troy ounces,) and with a 900mm diameter would be feet thick! Remember, in those days coins were worth their bullion weight. 870 grains is only a little over double the weight of a standard silver yen of that era, and since their diameter was 38.6mm, in .900 silver one the size of yours would be substantially heavier than the piece claims to be. The obverse design is similar to some early Chinese milled coins, but does not resemble any genuine Japanese coin. I'd give odds of 8-5 and half your money back if I lose that the one Eddyk found on EBay was offered by a Chinese seller. If not, it was undoubtedly from the sucker who bought it from China.
