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* Falls present attractive buying opportunities - traders
* Nikkei lost 10 pct, or more than 2,000 points, in past 5 days
* More than half of Topix's 33 subsectors turn positive
By Ayai Tomisawa
TOKYO, Aug 25 (Reuters) - Japan's Nikkei share average changed course in extremely volatile trading and rose on Tuesday morning after solid U.S. stock futures eased concerns a global stock rout rooted in China worries would continue.
At the outset, after shares plunged in New York, the Nikkei touched a fresh six-month low. But losses were trimmed after U.S. stocks futures was up 2 percent during Asian trade.
The selloff in risk assets gathered pace, with U.S. stocks posting their worst day in four years and European shares hitting seven-month lows as concerns about faltering growth in China with the lack of any additional state intervention exacerbated the rout.
The Nikkei rose 1.1 percent to 18,744.90 at the midday break after falling to as low as 17,747.50 , the lowest level since mid-February. In the five sessions through Monday, the Nikkei dropped 10 percent, or more than 2,000 points.
Volatility remained high. Early in the day, the Nikkei volatility index jumped 30 percent to 46.24, its highest level in more than two years.
"China is and has always been a risk. This risk has now come to the forefront," said Rie Shigekawa, portfolio manager at Fidelity Worldwide Investment in Japan. "But while downside risks are likely to persist for the time being, the Japanese market is in a consolidation phase rather than a free fall."
Most of the Topix's 33 subsectors turned positive, with banking and real estate stocks leading the gains.
Mitsubishi UFJ Financial Group jumped 4.4 percent, Mizuho Financial Group surged 4.3 percent and Mitsubishi Estate soared 3.2 percent.
Steelmakers and commodity stocks, which suffered the steepest declines earlier, still underperformed. JFE Holdings dropped 0.1 percent while trading houses whose earnings are heavily linked to commodity prices fell. Mitsubishi Corp and Sumitomo Corp were down 0.9 percent and 1.0 percent, respectively.
Although exporters faced selling after the yen strengthened to a seven-month high of 116.15 yen against the dollar overnight, some of them bounced back after opening lower during morning trade.
Sony Corp rose 5.3 percent, Alps Electric Co gained 7.4 percent and Murata Manufacturing Co soared 8.8 percent.
"People are punting to see that if there is a little bit of bounce overall for the broader markets," said a senior trader at a foreign brokerage. "Whether we are out of the woods or not, it's hard to say, but when you see the VIX spike to the level it did, you kind of think it's overdone."
Traders said that in Japan, the fundamental picture hasn't changed as corporate earnings remain well supported, valuations look attractive while firms are responding to calls for better governance.
"Japan has been the hostage to the global macro playing," the senior trader said, adding that this fall has presented attractive stock picking opportunities.
The broader Topix rose 1.5 percent to 1,502.53 and the JPX-Nikkei Index 400 gained 1.3 percent at 13,546.20. (Editing by Richard Borsuk)