Even after recent gains, the yen has slumped 4.9 percent in the past three months, the worst performer after Norway’s krone among 10 developed-nation currencies tracked by Bloomberg Correlation-Weighted Indexes. The dollar advanced 6.3 percent and the euro rose 1.9 percent.

The Bloomberg Dollar Spot Index fell for a third day before a report tomorrow forecast to show U.S. retail sales increased for a second month in November.

“Retail sales are really important tomorrow,” Steven Englander, head of Group of 10 currency strategy at Citigroup Inc. in New York, said by phone. “A good retail sales number would at least set investors up for putting on long-dollar positions at the beginning of next year.” A long position is a bet the dollar will increase in value. 

Eoin Treacy's view

Shinzo Abe’s decision to call a snap election introduced an uncertainty which will be resolved on the 14th. Considering how swiftly the Yen had fallen in the last few months, the prospect of an unfavourable result, however unlikely, has been enough for traders to take profits in what has been an overextended decline. 

The Dollar had rallied for seven consecutive weeks to test the psychological ¥120 level and some consolidation of that gain now appears to be unfolding.  This may result is some additional short-term volatility but a sustained move below ¥110 would be required to begin to question medium-term potential for additional Yen weakness.