Nikkei opens lower Thursday as strong yen hurt exporters. At 9:15 a.m., the 225-issue Nikkei Stock Average stood down 55. 57 points, or 0.60 percent, from Wednesday at 9,176.64. The broader Topix index of all First Section issues on the Tokyo Stock Exchange was off 3.43 points, or 0.45 percent, at 761. 37.