The yen whipsawed Friday, hitting a fresh multidecade low against the dollar, after Bank of Japan Gov. Kazuo Ueda disappointed traders seeking hints on further rate increases. + Some analysts say only bigger moves would trigger intervention by Japan's finance ministry. The central bank decided earlier in the day to maintain its recent target range for interest rates at 0% to 0.1%. Ueda left the door open for more rate increases, but suggested recent falls in the yen might not trigger immediate BOJ action.