TOKYO, Feb 19 - Japan's Nikkei stock average closed up on Thursday, with a softening of the yen against the dollar pushing blue-chip exporters higher and Shinsei Bank <8303.T> putting in a powerful market debut. The Nikkei benchmark <.N225> put on 0.72 percent or 76.99 points to end at 10,753.80, rebounding from a 0.23 percent slump the previous day. Shinsei, the first bank in Japan to be nationalised, sold to a private equity fund and then floated on the market, closed at 827 yen, 58 percent above its initial public offering (IPO) price. But while some of Japan's megabanks eased in response to the wildly popular IPO, market participants said some concerns that Shinsei's debut would suck funds from other sectors of the market had proved unwarranted. The weaker yen helped high-techs like electronics giants Sony Corp <6758.T> and Canon Inc <7751.T> make solid gains, while chip-equipment makers rose after strong earnings from U.S. peer Applied Materials Inc . The broad TOPIX index <.TOPX> gained 0.62 percent to 1,059.51. //