Nikkei opened 1.22 percent lower Thursday amid concerns over global growth following dismal U.S. corporate earnings reports. At 9:15 a.m., the 225-issue Nikkei Stock Average lost 162.86 points, or 1.22 percent, from Wednesday to 13,220.03. The broader Topix index of all First Section issues on the Tokyo Stock Exchange was down 12.29 points, or 1.08 percent, at 1, 123.72.