The dollar was marginally higher at 106.30 yen. Against the euro, offered some support by a less downbeat than expected Ifo sentiment survey in Germany.
The dollar inched up against the yen and held near a four-week high against the euro on Monday ahead of meetings of the Bank of Japan and U.S. Federal Reserve which investors on balance expect to be dollar-positive.
Alone among the major global central banks, the Fed has some good economic news to discuss after improved data signals and a bounce in jobs numbers for June.
In contrast, the question for many is not whether but by how much the Bank of Japan will ease monetary policy after a month in which it has repeatedly denied it will finance consumer and business spending more directly with some form of "helicopter money".
That adds up to a meeting that should be bad for the yen, although some strategists worry that anything short of a dramatic move by the BOJ may disappoint and squeeze those betting against the Japanese currency.
"The macroeconomic outlook is 100 percent focused on the Fed and the BOJ. Of the two there are positioning expectations more clearly built into the BOJ," said Richard Cochinos, a strategist with Citi in London.
He said Citi's expectations of a 20 basis point rate cut and 3 trillion yen of additional quantitative easing were probably in the middle of what the market expected.
"Short-term capital is positioning for dollar upside," he said. "To retain significant upside, for it to get above 110 yen, you're going to have to do more than just increase QE."
The dollar was marginally higher at 106.30 yen. Against the euro, offered some support by a less downbeat than expected Ifo sentiment survey in Germany, the dollar traded less than a quarter of a cent off Friday's four-week highs of $1.0955.
Upbeat U.S. business activity data on Friday added to prospects of a Federal Reserve interest rate hike within the year and supported the greenback.
Improved risk sentiment - Wall Street shares have hit consecutive record highs this month - has weighed on the Japanese currency, which has fallen roughly 7 percent against the dollar from a three-year peak reached soon after the Brexit referendum a month ago.
The Fed is widely expected to stand pat on monetary policy, and investors will be sifting through its statements for any hint of a near-term rate increase following recently firm U.S. economic indicators that have revived tightening expectations.
"Dollar/yen could test the 108 handle if the Fed's comments this week are supportive towards a rate hike and if the BOJ eases. On the other hand, the pair could drop below 105 if the BOJ stands pat as easing expectations are well entrenched," said Koji Fukaya, president of FPG Securities in Tokyo.
Fed funds futures rates on Friday priced in a 48 percent chance that the Fed will hike rates at its December meeting. A few weeks ago that probability was less than 20 percent.
The ongoing boon for risk assets is a key factor supporting the dollar and weakening the yen, but the headwinds commodity markets are beginning to face could reverse that trend.
After a bullish first half to the year, commodities-related currencies including the Canadian dollar have stalled somewhat in the past week on a more than 4 percent fall in oil prices.
Analysts from Italian bank Unicredit said they believed that would be temporary.
"The market may be too complacent in not pricing in an interest rate change (in Canada) for at least the next three years," they said.
"Over the next couple of quarters some (future) tightening will start to be priced in, which, together with the CAD's ongoing undervaluation, should bode ill for the USD-CAD."
The Canadian dollar inched down 0.2 percent to C$1.3153 per dollar.