The benchmark Nikkei 225 index rose 94.13 points to 9.529.14 by noon, while the Topix index added 4.12 points, or 0.48 percent, to 858.07. However, caution remained, with fragile optimism likely to erode on any setback in the delicate operations to restore power to overheating reactors at the Fukushima atomic plant, which was crippled by the earthquake and tsunami.

"Dramatic events in Japan and the Middle East/North Africa region just make the scenario of a consolidation in global recovery and a return to a more  widespread preference for risky assets more uncertain," said Credit Agricole in  a note to clients.

Despite slow progress in fully restoring power to the stricken Fukushima  Daiichi power plant, news some manufacturers were starting to resume production after the March 11 earthquake and tsunami encouraged buyers. Toyota Motor rose 1.39 percent to 3,260 yen after it said on Thursday I will resume production of three hybrid models in Japan on Monday. Nissan Motor added 2.23 percent. The automaker resumed production of some  parts earlier this week and assembly of some vehicles on Thursday. Tokyo Electric Power, which owns the stricken nuclear plant, was down 3.99 percent at 866.

Overnight, the Dow Jones Industrial Average gained 0.70 percent while the  broader S&P 500 rose 0.93 percent. Government data before the market opened showed a continuing decrease in applications for unemployment insurance, a sign that the labour market continues to improve, though still at a slow pace. The yen was little changed against the dollar at 81.00 yen from 81.01 yen overnight. It was softer against the euro at 114.80 yen from 113.61 yen. Japan and its G7 allies last week intervened jointly in currency markets  for the first time in a decade to calm turmoil sparked by the country's worst natural disaster in nearly a century, after the unit soared to a postwar high of 76.25 yen to the dollar.