Nikkei opened 0.59 percent higher early Tuesday morning. At 9:15 a.m., the 225-issue Nikkei Stock Average was up 76.92 points, or 0.59 percent, from Monday at 13,110.04. The broader Topix index of all First Section issues on the Tokyo Stock Exchange was up 7.94 points, or 0.73 percent, at 1,092. 66.