Tokyo stocks opened marginally lower Thursday as investor sentiment was initially dented by the yen's appreciation against the U.S. dollar.

As of 9:15 a.m., the 225-issue Nikkei Stock Average dropped 49.57 points, or 0.25 percent, from Wednesday to 19,679.71.

The broader Topix index of all First Section issues on the Tokyo Stock Exchange, meanwhile, lost 3.49 points, or 0.22 percent, to 1,612.51.

Mining, insurance and securities-linked issues comprised those that declined the most in the first few minutes after the opening bell.