TOKYO, Oct. 5 (Xinhua) -- Tokyo stocks opened lower Friday owing to investor consternation following Wall Street's decline overnight triggered by a spike in long-term U.S. Treasury yields.

As of 9:15 a.m., the 225-issue Nikkei Stock Average dropped 129.30 points, or 0.54 percent, from Thursday to 23,846.32.

The broader Topix index of all First Section issues on the Tokyo Stock Exchange, meanwhile, fell 5.51 points, or 0.31 percent, at 1,795.68.

Machinery, oil and coal product, and mining-oriented issues comprised those that declined the most in the opening minutes after the morning bell.