Nikkei retreats from 6-1/2 week high after dismal China data

* Nikkei rises 0.1 pct, Topix up 0.3 pct * Weak China trade data dents early gains By Tomo Uetake TOKYO, July 10 (Reuters) - The Nikkei share average eased on Wednesday from a 6-1/2 week high hit earlier in the session after unexpectedly weak Chinese trade data heightened concerns about growth in the world's second-largest economy and one of Japan's top export markets. The benchmark Nikkei rose 0.1 percent to 14,489.90 by the midday break in a choppy session. The index advanc