Nikkei opened 1.11 percent higher on Monday on a weaker yen, climbing to its highest level in five years and four months. At 9:15 a.m., the 225-issue Nikkei Stock Average was up 162.17 points, or 1.11 percent, from Friday at 14,769.71, after hitting 14,793.34, its highest intraday level since Jan. 4, 2008. The broader Topix index of all First Section issues on the Tokyo Stock Exchange was up 15.61 points, or 1.29 percent, at 1, 226.21.