TOKYO, Feb 14 (Reuters) - Japan's Nikkei share average failed to maintain early gains on Wednesday, and hit a four-month low as investor sentiment remained shaky ahead of U.S. inflation data due later in the day.
Nikkei average initially tracked gains on Wall Street shares to rise 0.6 percent but it quickly lost steam, dropping as much as 0.9 percent to 21,061.85 in morning trade, below last week's low of 21,078.71.
At the midday break, the Nikkei was at 21,109.29, off 0.64 percent for the day.
While the Nikkei's 200-day moving average, which stood around 21,000, is seen as a major support, a break of that level could worsen the battered sentiment, a real possibility if U.S. January inflation data triggers another rout in global shares.
The broader Topix dropped 0.7 percent to 1,704.47, slipping to its lowest levels since October, with small cap shares hit the most. The Topix Small dropped 1.2 percent.
Selling was broad-based, with about three-quarters of about 2,000 shares listed on the Tokyo Stock Exchange's main board in the red while only about one-fifth made gains.
The rise of the yen to a five-month high against the dollar is also clouding the outlook for Japanese exporters' earnings. (Reporting by Tokyo Markets Team; Editing by Richard Borsuk)