TOKYO, Feb 28 (Reuters) - Japan's Nikkei share average edged down on Tuesday after market participants took profits ahead of a key selling level at 9,700, while chipmaker Elpida Memory Inc was untraded with a glut of sell orders after seeking bankruptcy protection. The benchmark Nikkei slipped 0.6 percent to 9,573.61, while the broader Topix index eased 0.8 percent to 828.82.