You have $15,000 USD today and are willing to invest over a 3-year period. You have two choices:

i) Convert the money to Japanese Yen at the current FOREX spot rate. Then invest the Yen in a series of three 1-year interest-bearing time deposits. For example, after the first-year elapses and its interest accrues, you then invest the total proceeds (principle + interest) again for another year, and so forth.

OR,

ii) Invest the money in a 3-year USD time-deposit account.