In a stunning development early Monday morning, Banri Kaieda, president of the Democratic Party of Japan learned he lost his Diet seat in Sunday¡¯s Lower House election and is now set to quit as leader of the nation¡¯s largest opposition force.

It is unprecedented for the head of a political party, who generally receives wide media exposure, to lose a Diet seat in an election.

Kaieda¡¯s failure has underlined the DPJ¡¯s weakening grip on swing voters in urban areas, particularly in Tokyo, which is known for having a high concentration of such voters.