* Mazda outperforms on Credit Suisse upgrade * Sentiment seen staying positive as yen remains weak By Ayai Tomisawa TOKYO, Dec 2 (Reuters) - Japanese stocks edged down in choppy trade on Monday morning as investors turned cautious over the market's recent rapid pace of gains, while trading was thin ahead of major U.S. economic data due this week. The Nikkei stock average was down 0.2 percent at 15,638.91 points in midmorning trade. The benchmark was trading 5.2 percent above its 25-day moving average of 14,872.71, suggesting it has reached overbought territory in a short period of time. Last month, the Nikkei gained 9.3 percent on the back of strong corporate earnings and a weaker yen. It is within sight of a 5-1/2 year peak of 15,942.60 marked on May 23. "Most foreign investors are still away (for the U.S. Thanksgiving holiday). Some hedge buying from foreign hedge funds is seen, but they are not buying long," said Kyoya Okazawa, head of global equities at BNP Paribas. Exporters were mixed, with Toyota Motor Corp flat and Panasonic Corp falling 0.2 percent, while Sony Corp added 0.6 percent. Analysts said that going forward, sentiment was expected to remain generally positive as the weak yen trend is seen staying intact. The dollar rose about 0.1 percent to 102.55 yen, moving back towards a six-month high of 102.61 yen touched on Friday. A weak yen boosts exporters' competitiveness abroad and inflates their overseas profits when repatriated. Mazda Motor Corp gained 2.7 percent and was the most traded stock by turnover after Credit Suisse raised its rating on the carmaker to "outperform" from "neutral", citing expected strong sales of new models. Traders said retail investors' buying of domestic-demand sensitive stocks like financial firms was lifting the broader Topix, which gained 0.1 percent to 1,259.23. Mitsubishi UFJ Financial Group gained 0.6 percent, NKSJ Holdings added 1.1 percent and Sony Financial Holdings added 0.7 percent. On the U.S. data calendar, nonfarm payrolls data for November is scheduled for release on Friday. The Institute for Supply Management's factory index will be released later on Monday, and the ISM services index is due out on Wednesday.