* Dollar dips to 83.07 yen on EBS; 15-year low
* Japan PM Kan wins ruling party leadership vote
* Euro hurt by larger-than-expected drop in German ZEW index
* Dollar falls to 9-mth low vs Swiss franc, below parity (Adds quote, updates prices)
By Tamawa Desai
LONDON, Sept 14 (Reuters) - The dollar hit a 15-year low against the yen on Tuesday as Japanese Prime Minister Naoto Kan won the ruling party leadership vote, raising speculation Tokyo would not act immediately to stem the yen's rise.
Kan will keep his job after an unexpectedly decisive victory over party heavyweight Ichiro Ozawa, who had made more strident calls to curb the yen's advance.
By 0916 GMT, the dollar was down 0.5 percent to 83.25 yen, after dipping to 83.07 yen on trading platform EBS. Buying ahead of option barriers at 83.00 yen contained the downside, traders said. Stop-loss orders were seen below at 82.85/90 yen.
"With the market having positioned for a Kan victory, the scope for considerable further yen appreciation may be limited," said Derek Halpenny, European head of global currency research at Bank of Tokyo-Mitsubishi UFJ.
"The one negative aspect for Kan ... is that he only got 50.7 percent of the vote of Diet members. This hardly gives Kan a strong mandate for leading the country and we suspect once the markets focus on this aspect the yen may weaken back a bit."
Still, traders said any dollar rise may be short-lived, with Monday's 84.43 intraday peak seen as the first point of resistance, due to expectations Japanese exporters would sell more dollars before their half-year book closing on Sept. 30.
"The threat of intervention will hang over the market but will there be international cooperation? Probably no. So the market will continue to test Kan's resolve," said Simon Derrick, head of currency research in Bank of New York Mellon.
EURO SAGS ON ZEW
The euro edged near the day's low against the dollar of $1.2845 after the German ZEW economic sentiment index fell more than expected in September.
It held much of Monday's 1.6 percent gains on solid Chinese data and relief over new Basel III banking rules. A major resistance point was seen at $1.2920-30, a level that has blocked the currency several times since August.
The dollar fell below parity against the Swiss franc to hit a nine-month low of 0.9996 francs on EBS, and a one-month low against a basket of currencies. The greenback suffered its steepest fall against the euro in two months on Monday as investor risk appetite helped the single currency.
The dollar index was flat at 81.94, after touching a one-month low of 81.660 and piercing its 200-day moving average at 81.761. A clear break below the moving average could stoke expectations of further weakness in the U.S. currency.
Market players will look to U.S. retail sales data, expected to rise 0.3 percent in August from the previous month. A lower-than-expected reading could trigger further yen gains against the dollar, some traders said.
The yen also recouped some of its recent losses on the crosses, particularly against the Australian and New Zealand dollars which shed more than 1 percent.
The New Zealand dollar also dropped 0.8 percent to $0.7272 after weaker-than-expected New Zealand retail sales added to the case against a rate hike.