TOKYO (AFP) - Yoshihiko Noda became Japan's sixth new prime minister in five years Tuesday, inheriting an in-tray groaning with disaster recovery, nuclear crisis and economic gloom in the ageing, debt-choked nation. The outgoing finance minister takes the place of Naoto Kan, who resigned after just 15 months in office with rock-bottom poll ratings, perpetuating the country's chronic revolving-door leadership at a time of national crisis. Noda became his centre-left party's third premier, two years to the day since it won a landslide election that ended a half-century of conservative rule.