Despite his re-election as president of the ruling party, Prime Minister Naoto Kan maintained a serious face immediately following his victory Tuesday afternoon over Ichiro Ozawa.

Kan is well aware of the daunting political challenges that lie ahead, in particular the divided Diet and the ongoing power struggle within his Democratic Party of Japan, which many analysts say may result in a major realignment of political forces.

Now attention is pinned on Ozawa's next move, and whether he will continue his ambition to amass more power within the DPJ or leave the party altogether and form a new political force with some of his followers.