Japanese Prime Minister Naoto Kan will keep his job after an unexpectedly strong victory in a ruling party leadership vote on Tuesday, but must now strive to unify his party and forge deals with the opposition to pass laws in a divided parliament. Kan, 63, who has promised to curb spending and cap borrowing, is already struggling with a strong yen, a fragile recovery and public debt that is twice the size of Japan's $5 trillion economy. Markets had been braced for a shift toward more aggressive spending if Kan lost to Ichiro Ozawa, a scandal-tainted powerbroker who had said he would consider issuing more debt if the economy worsened.