Answer:
Other things equal U.S. exporters to Japan think this is good news and U.S. importers to Japan think this is bad news.
Explanation:
The Real Effective Exchange Rate is the average of a currency of a country concerning an index of other currency. A decreased USD-Yen REER is good news for U.S. exporters to they will earn more money for each item sold in Japan, but it is bad news for importers because they will pay more money for each item brought to the U.S.