The Bank of Japan decided to hold its policy steady earlier in the session and offered a bleaker economic view, but the widely-expected decision had little impact on local markets.
The won was quoted at 1,187.7 to the dollar at the conclusion of onshore trade, down 0.1 percent compared to Monday's close of 1,186.1.
South Korean shares edged lower after rising over the past four days.
The Korea Composite Stock Price Index (KOSPI) closed down 0.1 percent at 1,969.95 points.