TOKYO, Aug. 17 (Xinhua) -- Tokyo stocks opened higher Friday tracking gains on Wall Street overnight, with the market mood further brightened by a weak yen giving exporters a boost.

As of 9:15 a.m., the 225-issue Nikkei Stock Average gained 113.33 points, or 0.51 percent, from Thursday to 22,305.37.

The broader Topix index of all First Section issues on the Tokyo Stock Exchange, meanwhile, added 8.31 points, or 0.49 percent, to 1,695.46.

Marine transportation, mining, and precision instrument-linked issues comprised those that gained the most by the close of play.