The yen steadied slightly off a 2 1/2-year low against the dollar on Monday as option-related buying prompted short-term players to refrain from testing the Japanese currency's downside for now.
The euro rallied Friday on growing optimism the region's debt crisis has turned the corner, while the yen was headed for its 11th consecutive week of losses.
The yen tumbled 2 percent against the dollar to hit a 2 1/2-year low on Thursday after a Japanese official said the government has no problem with the dollar hitting 100 yen.
The yen pushed higher against the euro and dollar on Wednesday, extending gains from the previous day, when monetary easing from Bank of Japan fell short of some expectations for faster, more aggressive action.
The yen soared 1 percent against the dollar and euro on Tuesday after the Bank of Japan said its open-ended commitment to buy assets would kick in only next year.
U.S. Treasury debt prices were trading little changed as a U.S. Republican proposal for a limited rise in the debt ceiling curbed demand for safe-haven assets.
The yen briefly fell against the dollar on Tuesday after the Bank of Japan surprised markets by adopting an open-ended commitment to buy assets, but later regained ground as the new scheme for additional purchases only comes into effect next year.
Central banks around the world are furiously trying to boost their economies by lowering the value of their currencies, with CNBC's Bertha Coombs and Melissa Lee and the Money In Motion traders.
Oil is heating up this week, and rising tensions in Algeria are fueling the rally, with Dennis Gartman of The Garman Letter; CNBC's Melissa Lee and the Money In Motion traders.
Easing bets hit the yen, a rising euro dims the Swiss franc, China's fourth quarter GDP hits the mark, and the British aren't shopping - it's time for your FX Fix.
The yen hit a 2-1/2 year low against the dollar on Friday as markets positioned for the Bank of Japan to take bold action to tackle deflation at a policy-setting meeting early next week.