TOKYO, March 5 (Xinhua) -- Tokyo stocks opened lower Monday as a comparatively firm yen against the U.S. dollar soured the marked mood and dented exporter issues.

As of 9:15 a.m., the 225-issue Nikkei Stock Average dropped 109.03 points, or 0.51 percent, from Friday to 21,072.61.

The broader Topix index of all First Section issues on the Tokyo Stock Exchange, meanwhile, lost 8.19 points, or 0.48 percent, to 1,700.15.

Nonferrous metal, iron and steel and marine transportation-oriented issues comprised those that declined the most in the opening minutes after the rowing bell.