* Dollar/yen threatens to fall below 200-day average
* Yen helped by dwindling chance of near-term BOJ easing
* Dollar hampered by fall in U.S. bond yields, dovish Fed
* ECB easing expectations, election jitters hurt euro
TOKYO, May 20 (Reuters) - The yen held near a 3 1/2-month high against the dollar and the euro on Tuesday, supported by diminishing expectations of stimulus by the Bank of Japan as well as falling U.S. and European bond yields.
The dollar traded at 101.48 yen, a day after falling to 101.10 yen, its lowest level since early February -- briefly breaking below its 200-day moving average at 101.25 yen.
The chart break was a talking point among yen traders given the dollar had not stayed below that average except for brief forays in October-November last year. The dollar has largely been in a strong position since late 2012 when Japanese Prime Minister Shinzo Abe's embarked on aggressive fiscal and monetary easing to revive growth.
As a result a sustained fall below that mark may portend a turning point in the yen's weakening trend.
The uptick in the yen also comes at a time of decreasing expectations of near-term monetary easing by the Bank of Japan as Governor Haruhiko Kuroda has stuck to an upbeat assessment on the Japanese economy in recent weeks.
The BOJ is widely expected to keep it policy unchanged at a two-day policy meeting starting on Tuesday, with traders now looking to Kuroda's press conference after the meeting.
"If Kuroda makes dovish comments tomorrow, then the dollar/yen may manage to stay above the 200-day average. But if he intentionally stresses his optimistic economic views, markets will take it as a sign he accepts a higher yen and fall in stocks," said Osamu Takashima, head of FX strategy at Citigroup Securities in Tokyo.
The dollar has been facing some pressure of its own from falls in U.S. Treasury yields.
Mixed economic data and a generally dovish outlook from the Federal Reserve have weighed on U.S. bond yields, keeping dollar bulls in check.
On Monday, Dallas Fed President Richard Fisher and San Francisco Fed President John Williams added to the dovish tone.
Fisher, known for his hawkish views on monetary policy, said there have been positive aspects to the Fed's easy policy, while Williams, a dove, acknowledged weakness in the U.S. housing sector.
Williams added that it's not appropriate for the Fed to start raising interest rates until the second half of next year.
The benchmark U.S. 10-year yield, which hit a six-month low of 2.473 percent last week, has stood near that level since then.
The euro also fell to 3 1/2-month low of 138.62 yen on Monday and last fetched 139.16 yen.
Against the dollar, the common currency was steadier at $1.3712, little changed over the past few days, though it was not far from 2 1/2-month lows of $1.3648 hit last Thursday.
The euro has been pressured by soft euro zone growth data published on Thursday and expectations that the European Central Bank will adopt stimulus early next month.
The euro could come under more pressure ahead of potentially destabilising European Parliament elections later this week, where votes for anti-austerity, euro-sceptic parties look set to increase.
Yields on Italy and Spanish government bonds rose on Monday, as investors took profits on recent price gains as investors were concerned a rise of euro-sceptic forces could thwart reform efforts.