CHIBA (Kyodo) Toshihito Kumagai, supported by the main opposition Democratic Party of Japan, won the Chiba mayoral election Sunday, defeating a rival backed by the ruling camp and another opposition candidate.

The landslide victory for Kumagai in the city with a population of about 950,000 will give additional impetus to the DPJ, which recently won mayoral elections in the cities of Nagoya and Saitama, and further rock the Cabinet of Prime Minister Taro Aso, from which one member resigned Friday over a Japan Post-related row, ahead of a general election that must be held by fall.

The 31-year-old Kumagai, a former city assembly member also backed by the Social Democratic Party, will become the youngest mayor in Japan.