* Nikkei down 0.7 pct, Topix off 0.6 pct * Real estate shares down * GS Yuasa soars on battery JV with Bosch By Ayai Tomisawa TOKYO, June 20 (Reuters) - Japan's Nikkei share average fell on Thursday after Federal Reserve Chairman Ben Bernanke confirmed market fears that the U.S. central bank could trim its bond buying programme later this year, but a weakening yen lifted some exporters and limited the declines. The Nikkei was down 0.7 percent at 13,147.74 points by midmorning trade after briefly dipping below the 13,000 mark. "The market's weakness shows that the Fed's decision to indicate exit strategy was too soon," said Masaru Hamasaki, senior strategist at Sumitomo Mitsui Asset Management. Bernanke said on Wednesday the U.S. economy is expanding strongly enough for the Fed to begin slowing the pace of its $85 billion monthly purchases of Treasuries and mortgage-backed securities, with the goal of ending it in mid-2014. Real estate stocks were battered, with Mitsui Fudosan Co falling 2.4 percent, Mitsubishi Estate Co shedding 1.5 percent and Sumitomo Realty & Development tumbling 3.8 percent. But the yen's weakness limited losses, lifting some exporters, with Toshiba Corp gaining 1.3 percent, Mazda Motor Corp rising 3.0 percent and Sony Corp adding 0.7 percent. The dollar last traded at 96.60 yen, after rising as high as 96.93 yen on Wednesday. GS Yuasa Corp surged as much as 11.1 percent after the German industrial group Robert Bosch GmbH said it had agreed to work on next-generation lithium-ion batteries with the battery maker and Mitsubishi Corp. The broader Topix shed 0.6 percent. But analysts said that the negative impact from the Fed's stance should be short-lived as ending quantitative easing would mean that the Fed is confident that unemployment is falling and the real economy has returned to a self-sustained recovery. "If the Fed makes this shift, it would be difficult to imagine a prolonged downturn of U.S. and Japanese stocks because a transition would be taking place from monetary policies to corporate earnings as the driving force behind stock prices," Ryoji Musha, president of Musha Research, wrote in a note. Analysts also said that there are some technical signals showing that Japanese stocks have hit a bottom, noting that the Nikkei's 5-day and 25-day moving averages are rising. The Nikkei has lost 17 percent since hitting a 5-1/2 year peak on May 23 on concerns over Fed stimulus as well as slowing growth in China, Japan's second-largest export market, and disappointment over Prime Minister Shinzo Abe's growth strategy to revive the economy. It entered a bear market last week after dropping more than 20 percent from that multi-year high, but is still up 27 percent this year. On Wednesday, U.S. stocks fell more than 1 percent after Fed Chairman Bernanke said he expects to slow the pace of the Fed's bond purchase later this year if the economy was strong enough.