The yen appreciated to the strongest in almost four weeks versus the dollar after a gauge of U.S. manufacturing grew less than forecast, adding to haven demand and damping bets the Federal Reserve might slow its bond-buying under quantitative easing.

The Institute for Supply Management’s factory index fell to 51.3, the Tempe, Arizona-based group’s figures showed. The 2.9- point decline was the biggest since July 2011. The gauge reached 54.2 in February, the highest level since June 2011. Fifty is the dividing line between expansion and contraction.

Japan’s currency climbed versus all of its 16 most-traded peers before the nation’s central bank opens a policy meeting April 3. Bank of Japan Governor Haruhiko Kuroda will preside over his first policy meeting April 3-4. He said in testimony to parliament last week he wants to achieve a 2 percent inflation target in two years.

The euro fell against the yen before data tomorrow that may show unemployment in the currency bloc climbed to a record, two days before European Central Bank officials announce an interest-rate decision. Unemployment in the euro area probably climbed to a record 12 percent in February, according to a survey of economists before the European Union’s statistics office releases the report tomorrow. A final reading of a gauge tracking manufacturing in the region also due tomorrow may confirm a 20th month of contraction, a separate poll showed. ECB President Mario Draghi and his fellow policy makers will probably keep the euro area’s benchmark interest rate at a record-low 0.75 percent at a meeting April 4, according to analysts surveyed.