1. The Japanese currency is again a very interesting topic, it doesn't make you the millionaire in a minute but at least you are richer compared to Indian Rupees, US Dollars or Euros. But it isn't a cheap country at all.
2. The currency is called as Japanese Yen and is abbreviated as JPY.
3. You can either carry JPY from your own country or you can exchange it at the hotel or other areas you are staying at.
4. Remember that unlike other countries, you do not get to see exchange counters in Japan, but a hotel or a market area is generally equipped with a currency exchange machine, where you just follow the instructions mentioned on the machine and get your exchange, whether it be paper currency or it be coins.