Japanese shares open lower Thursday morning, tracking falls on Wall Street due to concerns of the global economic outlook. In the first 15 minutes of trading, the benchmark 225-issue Nikkei Stock Average fell 52.94 points, or 0.60 percent, from Wednesday to 8,719.60. The broader Topix index of all First Section issues on the Tokyo Stock Exchange was down 4.64 points, or 0.62 percent, to 746. 85.