* Japan intervenes for first time in six years
* BOJ continues to buy dollars in European session
* Dollar rises to 85.53 yen, key resistance at 86.40
(Adds quotes, changes dateline, Previous TOKYO)
By Neal Armstrong
LONDON, Sept 15 (Reuters) - The dollar jumped more than two yen from a 15-year low after Japan intervened to sell yen for the first time in six years, but with key chart levels yet to break, traders were sceptical the impact would be lasting.
The intervention helped send the euro, Australian dollar and sterling sharply higher on the day against the Japanese currency, although traders doubted Japan had bought anything other than dollars for yen.
Finance Minister Yoshihiko Noda said Japan intervened in the currency market as the impact of the yen’s rise on the economy could not be ignored and that Japan would continue to take action, but that it had been acting alone.
Estimates on how much yen selling Japan had done in Asia varied widely. Dealers cited talk of 300-500 billion yen ($3.6 billion-$6 billion) although some reports put it closer to 100 billion yen.
The Bank of Japan acts for the Ministry of Finance in intervention, which traders said continued in the Asian and European sessions after an initial bout at around 83 yen per dollar shortly after the dollar hit a 15-year low of 82.87 yen.
At 0810 GMT, the dollar was up 2.7 percent at 85.40 yen JPY=, close to a session high of 85.53 hit on trading platform EBS. The euro was 2.8 percent higher at 110.78 yen EURJPY=R after making a brief show into its Ichimoku Cloud, an indicator used to gauge momentum and future areas of support and resistance, at 111.01.
“I think we’re now going to see persistent official buying of dollar/yen in the near-term,” said Adam Cole, head of currency strategy at RBC Capital Markets.
“But in the long term I’m not sure it will be sustained as the current administration is less interventionist than the LDP, who were in power during the last bout of intervention in 2004.”
Traders said official intervention persisted into the European session, with buying of dollars reported in the 84.95/85.00 area and at 85.25 on trading platform EBS.
“I’m not expecting the multiple big fig(ure)-spike type intervention they have used in the past. My order board has little to suggest there’s enough traction at present,” a trader at a U.S. bank in London said.
Some stop-losses were reported at 85.75, but technical analysts said the focus remained on the downside while dollar/yen held below key resistance at 86.40, which is the bottom of the closely watched Ichimoku Cloud. <^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
For dollar/yen correlations link.reuters.com/wyn43p
For PDF on the yen's rise r.reuters.com/zuz33p
For graphic on intervention link.reuters.com/qep63p
For Reuters Insider on yen link.reuters.com/sav63p
The Bank of Japan started buying the dollar from around 10:30 a.m. (0130 GMT) on Wednesday.
Sources familiar with the matter said the central bank was ready to leave the intervention unsterilised -- holding off draining the funds that went into the currency market through the yen selling. [ID:nTKX006996]
The action was Japan’s first currency market intervention since March 2004, when it halted a 15-month campaign to sell the yen. Then it sold a total of 35 trillion yen.
Noda said Japan would take decisive steps if necessary, including intervention, and watch currency market moves closely.
Analysts said the impact of intervention would diminish.
“In the longer run, intervention is likely to lose its power. As the G20 is calling for flexibility in currencies, intervention will be only for smoothing. Unilateral interventions also have limited impact,” said Minori Uchida, senior analyst at Bank of Tokyo-Mitsubishi UFJ.
The yen gained fresh momentum on Tuesday after Japanese Prime Minister Naoto Kan won a leadership ballot against a rival seen as more willing to intervene to weaken the currency.
The dollar was also hurt early on by talk, ahead of a policy meeting next week, that the Federal Reserve could be nearing more quantitative easing .
The dollar was flat against the euro at $1.2995 EUR=.
The Australian dollar shot to its highest in nearly three months at 79.98 yen AUDJPY=R.