The yen weakened past 145 per dollar, setting the stage for Japan s authorities to intervene to prop up the currency for a second time this year.
Japan's currency fell by as much as 0.4% to 145.30. Policy makers in the nation had intervened on Sept. 22 to contain losses that had reached 20% this year.
The decline of the yen highlights the difficulty to shore up the currency, as the Bank of Japan maintains an accommodative policy and yield-curve control even as the Federal ReserveFederal Reserve raises interest rates.
As long as the BOJ YCC remains in status quo and other central banks, including the Fed, the yen is at risk of further depreciation, according to Christopher Wong, a strategist at Oversea-Chinese Banking Corp.