TOKYO, March 13 (Reuters) - Japan's Nikkei share average edged down to a 1-1/2-week low on Thursday, erasing earlier gains after weaker-than-expected Chinese output and retail sales data disappointed the market. The Nikkei ended down 0.1 percent at 14,815.98, the lowest closing level since March 4. It had risen as high as 14,919.84 earlier following strong Japanese machinery orders data. The broader Topix index shed 0.3 percent to 1,203.46. The JPX-Nikkei Index 400, a gauge comprising firms with high return on equity and strong corporate governance, dropped 0.3 percent to 10,885.43.