Tokyo stocks opened lower Tuesday morning on halt of the yen's depreciation. In the first 15 minutes of trading, the 225-issue Nikkei Stock Average fell 68.76 points, or 0.45 percent, from Monday to 15,095. 54. The broader Topix index of all First Section issues on the Tokyo Stock Exchange was down 4.08 points, or 0.33 percent, to 1, 237.59.