At an extraordinary convention of the Democratic Party of Japan in Tokyo on Sept. 21, DPJ leader Ichiro Ozawa surprised party members by declaring that the upcoming Lower House election will be his last opportunity to lead a nationwide political campaign.

Saying he is nearing his limits, physically and mentally, Ozawa thus ruled out the possibility of staying at the helm of the party much longer, even if the DPJ wins in the coming election.

This has stirred much speculation over who would succeed him as the head of the No. 1 opposition group. Three names have been mentioned as likely candidates: Naoto Kan, who is Ozawa's deputy; Yukio Hatoyama, currently DPJ secretary general; and Katsuya Okada, deputy head of the DPJ.

The outcome of the race for the DPJ leadership would depend much on how the party fared in its bid to depose the coalition government of the Liberal Democratic Party and Komeito and on the circumstances in which Ozawa would step down or be forced to resign.

Ozawa is known to have chronic heart disease. Even while the Diet is in session, he usually rests for about two hours after lunch every day. That is why he seldom takes his seat in the Lower House chamber when a plenary session is convened at 1 p.m.

One junior DPJ legislator was quoted as saying that if the party wins in the impending election, Ozawa would not be able to run the government for any more than six months.

Kan, whose constituency is in Tokyo, appears to be bent on playing a principal role in leading the party to election victory in the nation's capital so that he can consolidate his position as Ozawa's successor. The DPJ lost badly in Tokyo in the previous Lower House election in 2005, when the LDP scored a resounding victory nationwide on the coattails of then Prime Minister Junichiro Koizumi's slogan of privatizing the postal services.

Kan is now urging his colleagues in Tokyo to work toward winning in at least 15 of 25 constituencies there, believing that a major triumph in Tokyo would improve the chance of his succeeding Ozawa. His archrival is secretary general Hatoyama, who has been pushing intraparty activities to win support.

Hatoyama and Kan headed the party alternately between its founding in 1998 and 2004. Although they cooperate with each other on the surface to support Ozawa, their ulterior motives lie elsewhere.

Seeking to take advantage of the rivalry between the two is Okada, who is the symbol of anti-Ozawa forces within the party. He believes he is best qualified to take the helm of the party affairs after Ozawa steps down, and says the party must continue its endeavors for a government change regardless of the outcome of the Lower House election.

Each of these three hopefuls has drawbacks, however. Hatoyama comes from a family with an unusual political lineage: His grandfather was a prime minister, his father was a foreign minister, and his younger brother is the incumbent minister of internal affairs.

Yet, he lacks leadership. Last year, he proved himself incapable of stopping Ozawa from making the reckless move of trying to form a "grand coalition" with the LDP or opposing the government's appointment of a new governor of the Bank of Japan. Some within the party fear that should Hatoyama succeed Ozawa, that would only pave the way for Ozawa to continue exercising power from behind the scenes.

Kan, meanwhile, has been a loyal spokesman for Ozawa, and has done little other than support the latter's policies concerning road-related taxes. This has led younger members of the party to suspect that no generational change would be achieved if Kan became their next leader. Though well-versed in policy matters, Okada has a bad track record of having had to resign from the party leadership after the DPJ was roundly defeated in the 2005 Lower House election by Koizumi's LDP. He disappointed his followers when he declined to run against Ozawa in the election of the party leader this past summer, saying, "If I garner a large number of votes, that could create a schism within the party."

Are there other candidates to succeed Ozawa? Simply, no. The reason is that the power structure within the DPJ has been so much concentrated in the hands of Ozawa that no political aspirants can win party recognition or receive campaign funds without his approval.

Prominent figures like Banri Kaieda and Tetsundo Iwakuni, both known for their distant attitude toward Ozawa, were not on the initial list of DPJ candidates for the next Lower House election. Under these circumstances, some young party members with weak financial resources are afraid to speak up.

If the DPJ wins the next Lower House election and forms a government with other opposition groups to replace the current coalition of the LDP and Komeito, and if the new Ozawa administration lasts for a reasonable period of time without blunders, the party leadership will most likely be handed over peacefully to either Kan or Hatoyama.

If, on the other hand, Ozawa fails to perform his duties as prime minister and gives up his post as the LDP's Yasuo Fukuda and Shinzo Abe did, Okada's name would surface as champion of groups opposing Ozawa.

Should the DPJ lose in the Lower House election and the current LDP-Komeito coalition survives, Ozawa is most likely to step down, according to most party leaders. In that event, a number of candidates will run for the party leadership, but Hatoyama will probably be the first to be eliminated because, as secretary general of the party, he would be held responsible for the election defeat. The resulting showdown will be between Kan and Okada.

Uncertainty will prevail if the DPJ wins more Lower House seats than any other party even as the current coalition prevails as a majority to form a new government. In such a case, the party leadership race will be open not only to Kan and Okada but also to Hatoyama, with the possibility of members of younger generations running against them.

If the DPJ fails to win enough seats to form its own government, an intraparty conflict of one form or another is likely. The loser of that conflict will probably leave the party. Ozawa himself may choose to leave with his closest followers. There is talk of a scenario in which Ozawa's group would form a coalition with the LDP.

This is an abridged translation of an article from the October issue of Sentaku, a monthly magazine covering the Japanese political, social and economic scene.