The Democratic Party of Japan looks set for a three-way race to select its new head next month. The current leader, Mr. Naoto Kan, and the deputy secretary general, Mr. Yukio Hatoyama, have already announced they will run in the Sept. 25 party election. The third man, Mr. Takahiro Yokomichi, chairman of the executive council, is expected to declare his candidacy today.

Because the contest will be a close one, it could spur a vigorous policy debate in the largest opposition party, which has shown signs of disunity of late. With the Liberal Democratic Party and the Liberal Party moving toward a ruling coalition with New Komeito, the second-largest opposition party, the central issue in the race is how the DPJ will be able to counter the three-party alliance.

Mr. Kan has come under fire from some of his party rank and file for lackluster handling of party and parliamentary affairs. That is believed to have motivated Mr. Hatoyama, a longtime ally of Mr. Kan's, to run against him. With the party's founding leader now challenged by two heavyweight contenders, the coming contest also could widen divisions in the party.