The yen dropped to a two-month low against the dollar and a four-year trough versus sterling on Friday after Federal Reserve Chair nominee Janet Yellen's dovish remarks boosted risk appetite, undermining the low-yielding Japanese currency.
Yellen defended the U.S. central bank's stimulus to spur growth and called efforts to boost hiring an "imperative", reinforcing investors' expectations that U.S. monetary stimulus may be in place for an extended period.
The dollar rose as high as 100.31 yen and last stood at 100.26 yen, up 0.2 percent from late U.S levels. The British pound soared above major resistance at 160 yen and rose to 161.14 yen, its highest level since September 2009.
(Read more: Markets soothed by Yellen, watching data)