Here is the proof coin set I bought at the Japan Mint’s store in Tokyo. The coins range from 1 yen (aluminum), a 5 yen brass coin, a 10 yen bronze coin and a 50 yen cupronickel coin, to a 100 yen cupronickel coin and a 500 yen nickel-brass coin. The ¥500 yen coin is worth big bucks, about US$6.50! And what the little 1 yen coin has going for it, is that it can float on water- wow. What a nice demonstration of surface tension in water. (The picture is from the web. I have some used 1 yen coins and I will try that when I get home to Seattle !).