Nikkei posts biggest daily gain in two weeks as weak yen powers exporters

TOKYO, Sept 18 (Reuters) - Japan's Nikkei share average closed at a new eight-month high and posted the biggest daily rise in two weeks on Thursday, with a weak yen giving exporters a boost despite disappointing trade data which showed the softer currency is not significantly buoying sales. The Nikkei share average ended 1.1 percent higher at 16,067.57 points, the highest closing level since early January. It was the biggest daily percentage gain in two weeks. The broader Topix rose 1.0