TOKYO, March 10 Japanese shares retreated from a five-week high on Monday as disappointing Chinese trade data and uncertainty over the crisis in Ukraine prompted investors to lock in recent gains. Although the U.S. nonfarm payrolls report released on Friday was surprisingly strong, it provided limited support because it also cemented expectations of a further reduction in U.S. monetary stimulus. The benchmark Nikkei closed down 1 percent at 15,120.14, slipping from a five-week peak hit on Friday, in thin trading volume. Data released on Saturday showed Chinese exports unexpectedly tumbled in February, swinging the trade balance into deficit and adding to fears of a slowdown in China, one of Japan's biggest export markets. The broader Topix index shed 0.8 percent to close at 1,227.61, with 1.88 billion shares changing hands, the lowest volume since Aug. 26. The JPX-Nikkei Index 400, a recently introduced gauge comprising firms with high return on equity and strong corporate governance, ended down 0.8 percent at 11,105.11.