The dollar traded at 101 yen, its lowest level since early February. Against the euro, it gained less than 0.1 percent.
The euro could face some pressure ahead of potentially destabilizing European Parliament elections later this week, where votes for anti-austerity, eurosceptic parties look set to increase.
Yields on Italian and Spanish government bonds rose on Monday, as investors, concerned that a rise in eurosceptic support could thwart reform efforts, took profits on recent price gains.
Yields were slightly lower on Tuesday but any broader slackening off of interest in the periphery would be a bearish sign for the euro.
The jury is out on the fate of the single currency ahead of next month's European Central Bank meeting. Markets now firmly expect a cut in interest rates, but it remains to be seen whether that will be enough to counter the picture of positive capital flows that have kept the euro surprising on the upside against the dollar this year.
Much will depend on what other kinds of action, if any, the ECB takes or hints at. In that light there are several more speeches due from bank officials on Tuesday.
The BOJ is widely expected to keep its policy unchanged at a two-day policy meeting starting on Tuesday, with the market's attention focused instead on Governor Haruhiko Kuroda's news conference.
Kuroda has stuck to an upbeat assessment on the Japanese economy in recent weeks, dousing immediate easing expectations.