Mazda Motor Corp., a third owned by Ford Motor Co., rose to the highest since February, while Nintendo Co. jumped the most in two weeks. The yen fell 1.4 percent versus the dollar this week, increasing the value of Japanese exporters' overseas sales.
The Nikkei 225 Stock Average advanced for a fourth-straight day, rising 78.15, or 0.6 percent, to 13,476.45 at the close of trading in Tokyo, reversing an earlier 0.6 percent decline. The broader Topix index rose 10.74, or 0.8 percent, to 1,304.06.
The Nikkei added 1.2 percent in the past five days, extending gains to a fifth week, the longest string of advances since October. The Topix climbed 2 percent this week. Volume on the Tokyo bourse was 1.7 billion shares today, the third-lightest full day of trading this year.
Gains accelerated in the afternoon after Japan's Cabinet Office said consumer confidence rose from a five-year low as households became more optimistic about jobs. The sentiment index climbed to 36.7 last month, snapping a five-month decline.
Daito Trust Construction Co. led a drop by builders after the Nikkei newspaper said prices for cement and steel beams jumped, reducing the profit outlook for the companies.
Mazda, which exports four-fifths of its production, surged 5.9 percent to 414 yen, the third-biggest gain on the Nikkei and the highest since Feb. 29. Nintendo, Japan's largest game software developer, rose 4.6 percent to 55,000 yen in Osaka. Toyota Motor Corp., Japan's largest automaker, climbed 2 percent to 5,110 yen.
The yen traded at 102.36 per dollar today, on course for a 1.4 percent five-day decline. The Japanese currency touched a three-month low against the euro yesterday and has fallen 2.6 percent versus the Australian dollar this week.
Banks and developers drove gains on the Nikkei this week on growing sentiment that credit-market gridlock will ease, allowing lending to recover. The index has risen 13 percent from its two- year low on March 17, paring its loss this year to 12 percent.