The JPX-Nikkei 400 Index was launched in January 2014 as a means of revitalizing the Japanese equity market. The JPX-Nikkei 400 Index employs a rigorous screening process based on return on equity, cumulative operating profit and market capitalization to  select high-quality, capital-efficient Japanese companies.

U.S. ETF investors can also track the benchmark index through relatively new offerings, including the Deutsche X-trackers Japan JPX-Nikkei 400 Equity ETF (NYSEArca: JPN) and iShares JPX-Nikkei 400 ETF (NYSEArca: JPXN). However, JPN was down 2.2% and JPXN was 1.4% lower after the BOJ’s lackluster announcement on Friday.

Meanwhile, the CurrencyShares Japanese Yen Trust (NYSEArca: FXY) rose 1.1% Friday, with the U.S. dollar dipping 0.9% to ¥121.4, as traders turned to safe-haven assets. [Currency ETFs That Provide Port in Stormy Markets]

Currency-hedged JPX-Nikkei 400 ETFs faired slightly better than the non-hedged counterparts as the yen strengthened. On Friday, the Deutsche X-trackers Japan JPX-Nikkei 400 Hedged Equity ETF (NYSEArca: JPNH), the currency-hedged equivalent of JPN, fell 2.0% and the iShares Currency Hedged JPX-Nikkei 400 ETF (NYSEArca: HJPX), the currency-hedged version of JPXN, dropped 1.2%.

For more information on Japan, visit our Japan category.

Max Chen contributed to this article.