Nikkei opened sharply higher and topped 13,000 Friday morning on the Bank of Japan\'s bolder-than- expected monetary easing measures, hitting the highest level since August 2008. At 9:15 a.m., the 225-issue Nikkei Stock Average gained 456.11 points, or 3.61 percent, from Thursday at 13,090.65, after advancing as high as 13,225.62. The broader Topix index of all First Section issues on the Tokyo Stock Exchange was up 43.79 points, or 4.22 percent, at 1, 081.55.