The benchmark Nikkei stock index extended its winning streak for a 10th straight day on Monday following Wall Street's solid lead late last week, with investor sentiment also bolstered by optimism for solid corporate earnings.

The 225-issue Nikkei Stock Average added 100.38 points, or 0.47 percent, from Friday to close the day at 21,255.56, marking its highest close since Nov. 27, 1996.

The broader Topix index of all First Section issues on the Tokyo Stock Exchange, meanwhile, gained 10.56 points, or 0.62 percent, to close at 1,719.18.

Traders here said that along with U.S. shares advancing late last week, exchange rates suggesting that corporate earnings will be robust here, supported buying ahead of earnings season swinging into full gear later this month.

"The market was pushed up by solid U.S. shares, with the tech-heavy Nasdaq Composite Index ending at another record high," Yutaka Miura, a senior technical analyst at Mizuho Securities Co. was quoted as saying.

On corporate earnings, Takuya Takahashi, a strategist at Daiwa Securities, said that "the current foreign exchange level suggests that manufacturers' earnings will be bright."

Local brokers also said that large cap issues were also being snapped up as, on a global basis, they are still deemed to be undervalued.

"It is a buyback market rather than a buying market," Makoto Sengoku, a market analyst at Tokai Tokyo Research Institute, said, adding, "Overseas market players are having another look at the Japanese market with Tokyo shares' rising performance.

By the close of play, insurance, securities, and iron and steel-linked issues comprised those that gained the most, and rising issues beat declining ones by 1,204 to 741, on the First Section, with 85 ending the day unchanged.

Large cap issues found favor, including tech-oriented issues, with Advantest Corp. advancing 3.1 percent and Hitachi Ltd. rising 1.8 percent. Sony Corp., meanwhile, added 1.1 percent.

Financial issues also closed in positive territory, with Mitsubishi UFJ Financial Group adding 1.5 percent and Mizuho Financial Group gaining 1.4 percent.

Issues that gained on individual news included SoftBank Group, which gained 1.3 percent to close at 9,983 yen, following reports of a soon-to-be-announced merger between its U.S. unit Sprint Corp. and T-Mobile US Inc. of Deutsche Telekom AG.

On the main section on Monday, 1,801.25 million shares changed hands, dropping from Friday's volume of 1,847.95 million shares.

The turnover on the first trading day of the week came to 2,648.2 billion yen (23.65 billion U.S. dollars).