Nikkei opened 1.28 percent higher Friday morning on a weaker yen and signs of a global economic recovery. At 9:15 a.m., the 225-issue Nikkei Stock Average increased 179. 04 points, from Thursday at 14,184.81. The broader Topix index of all First Section issues on the Tokyo Stock Exchange was up 15.70 points, or 1.35 percent, at 1, 179.09.