* Dollar/yen pulls back from dip to 91.94 yen
* Japan margin traders cut dollar/yen net longs
* Investors await comments by ECB's Trichet
By Kaori Kaneko
TOKYO, Sept 3 (Reuters) - The yen retreated from a seven-week high against the dollar on Thursday after a rally in Chinese shares prompted investors to trim holdings of the low-risk Japanese currency, helping the dollar and euro.
The yen also gave back some of its gains against other major currencies but price action was subdued as investors refrained from building large positions ahead of pivotal U.S. non-farm payrolls figures on Friday.
The Shanghai Composite Index was up nearly 4 percent, although Tokyo's Nikkei share average dipped 0.4 percent while S&P futures were mildly positive.
"After dollar/yen and cross/yen managed to stay above the day's low hit earlier, investors took their cue from a rise in Shanghai shares amid few other incentives in Asian trade," said a trader at a Japanese bank.
"But the move was only moderate as investors usually keep their positions light before U.S. non-farm payrolls data."
Dealers said sentiment has tilted to being more sensitive to weaker economic news as stocks have been staggering recently, dampening the appetite to pursue gains in higher-yielding currencies and supporting the low-yielding yen.
"Weaker figures will likely have more impact on the market now, given it has not shown much reaction to better numbers recently," said Tomohiro Nishida, treasury department manager at Chuo Mitsui Trust and Banking Company.
Economists polled by Reuters expect Friday's payrolls report to show job losses of 225,000 for August, the lowest for any month since August 2008, after 247,000 workers were laid off in July.
The dollar fell as low as 91.94 yen on trading platform EBS on Thursday, its lowest since July 13, as investors continued to cut dollar holdings after a weaker-than-expected U.S. private-sector jobs report on Wednesday.
The U.S. currency later edged back to 92.37 yen, up 0.2 percent from late U.S. trade on Wednesday.
Dealers said a sustained break of 92.00 yen was likely to see the dollar test July's low of 91.73 yen and some cautioned a weaker payrolls reading could drive it down to the 90 yen level.
Jonathan Cavanagh, a currency strategist at Westpac, said however, that below 92 yen was a good opportunity to go long on the dollar ahead of the U.S. jobs figures, which could be better than the market was expecting.
Margin traders at the Tokyo Financial Exchange cut their net long positions in dollar/yen by 84,125 contracts to 24,601 contracts on Wednesday, when the dollar slid to a seven-week low of 92.10 yen on EBS.
Such position unwinding likely contributed to the dollar's fall on Wednesday, said Tomoko Fujii, a senior currency strategist at Bank of America Securities-Merrill Lynch.
"This also means that the remaining positions are very light so further position pressure from these people must also be lighter," Fujii said.
Against a basket of currencies the dollar was steady at 78.387.
ECB IN VIEW
Investors were also waiting for a monetary policy meeting later on Thursday by the European Central Bank at which policy-makers are expected to keep interest rates at 1.0 percent.
But ECB President Jean-Claude Trichet may caution against growing talk of a speedier recovery in the eurozone.
The euro fetched $1.4274, edging up 0.1 percent from late U.S. trade on Wednesday.
Against the yen, the euro was up 0.2 percent at 131.83 yen after touching seven-week low of 131.01 yen on EBS the previous day.
The Australian dollar rose 0.3 percent to $0.8358 and was at 77.17 yen, up 0.4 percent on the day.
The Aussie jumped nearly 1 percent on Wednesday after robust second-quarter gross domestic product numbers boosted expectations for a near-term rate hike. (Additional reporting by Masayuki Kitano and Charlotte Cooper in Tokyo and Anirban Nag in Sydney; Editing by Michael Watson)