The dollar and euro made their largest percentage gains against the yen since late 2008 on Thursday after the Bank of Japan surprised the markets with an ambitious plan to fight deflation in a radical overhaul of policy.
The dollar rose more than 3 percent and the euro more than 4 percent versus the yen after BOJ unleashed the world's most intense burst of monetary stimulus, promising to inject about $1.4 trillion into the economy in less than two years, a radical gamble that sent its bond yields to record lows.
Governor Haruhiko Kuroda, chairing his first policy meeting, committed the BOJ to open-ended asset buying and said the monetary base would nearly double to 270 trillion yen ($2.9 trillion) by the end of 2014.
(Read More: BOJ Throws in Kitchen Sink in War With Deflation)
"This is not your grandfather's BOJ," said Boris Schlossberg, managing director of FX Strategy at BK Asset Management in New York. "The fact that they came out, doubled the size of the QE and are willing to do all these non-conventional measures suggested that they really want to take dollar/yen to 100," he said.