The CurrencyShares Japanese Yen Trust (NYSEArca:FXY) is a fund that does just that, serving up access to the yen without tapping into equities. DXJ's momentum particularly picked up after WisdomTree changed the ETF's indexing methodology in November to emphasize companies with big export profiles-the very kinds of firms that stand to benefit the most from a weakening yen. From a fundamental perspective, since the prime minister took office in December, the Bank of Japan has already committed to double its inflation target to 2 percent and agreed to support an asset-buying program that could reach $1 trillion this year.