Nikkei closed 0.04 percent lower Monday.
The 225-issue Nikkei Stock Average fell 3.72 points, or 0.04 percent, to 8,929.34. The broader Topix index of all First Section issues on the Tokyo Stock Exchange fell 0.93 point, or 0.13 percent, to 740.30.
Honda Motor's downward revisions to its full-year earnings forecasts pushed the key indexes into negative territory in the afternoon.
Decliners included automakers, insurers and rubber products makers. Gainers included real estate developers, textile makers and utilities.
The turnover was about 917.8 billion yen (about 11.52 billion U. S. dollars).