* Dollar index falls to lowest level in six months
* Dollar lowest since Japan intervened last week
* Euro at 5-month high versus dollar
* Next euro target around $1.3465 - technical analysts (Updates prices; adds comment, details, changes byline)
By Steven C. Johnson
NEW YORK, Sept 22 (Reuters) - The dollar hit a five-month trough against the euro on Wednesday and fell to its lowest level against the yen since Japan's intervention as markets braced for more monetary easing from the Federal Reserve.
The Fed hinted on Tuesday that it might start pumping billions of new dollars into the economy, likely via purchases of Treasury bonds, to boost growth. That would further depress U.S. yields, in some cases already at record lows, and weaken demand for U.S. assets.
That pushed the euro above $1.34 for the first time since April and sent the dollar index, a gauge of the greenback against six major currencies <.DXY>, to a six-month low.
Gains in the euro
The Fed "is worried about deflation, which could bring forward more quantitative easing," said Andrew Wilkinson, chief analyst at Interactive Brokers' Group. "People don't like that prospect, so the market is punishing the dollar."
Traders were wary of pushing the dollar too low against the yen for fear it could trigger another round of intervention by Japanese authorities, who surprised the market last week by selling yen in the market for the first time in six years.
"Sellers will have to be very nimble as intervention risks are very high," said Paul Mackel, director of currency strategy at HSBC Markets. "We would expect the Japanese to intervene once the price action gets too one-sided."
The dollar was last down 0.8 percent at 84.42
Traders said Japan may step in between 83 and 85 yen and said authorities had called banks to ask if they will be staffed on Thursday, a Japanese national holiday, in an apparent attempt to keep traders cautious over intervention.
"I think they will intervene if the dollar falls to 84 yen or below," said Tom Levinson, FX strategist at ING. "Dollar/yen is pretty sensitive to the fall in U.S. yields, so it looks like pressure will be back on the Japanese authorities."
Japanese Prime Minister Naoto Kan kept investors nervous by telling the Financial Times that intervention was "unavoidable" if there was drastic change in the currency. For details, see [ID:nLDE68K2AL]
But David Gilmore, principal of FX Analytics, said the odds of intervention before Kan meets with U.S. President Barack Obama this week in New York are "virtually zero regardless of the level or pace of decline."
EURO APPEAL GROWS
The euro was sharply higher for a second straight day,
rising as high as $1.3440 before retreating to $1.3380
After closing above its 200-day moving average on Tuesday, technical analysts said the next target was around $1.3465, the 38.2 percent retracement from a 2008 high of $1.6038, to June's low of $1.1875.
The dollar also hit a 2-1/2-year low of 0.9837 Swiss francs
Steven Englander, who heads Citigroup's global G10 currency strategy, said there are several reasons to buy the euro from here, one of which being that the market "is at best neutral euros and very probably still short."
Wilkinson added that investors seem genuinely more relaxed about the euro zone outlook and debt levels of some troubled countries, as evidenced by solid bond auctions in Ireland, Greece and elsewhere. (Additional reporting by Vivianne Rodrigues in New York and Anirban Nag in London; Editing by Kenneth Barry)