The three candidates seeking to become Japan's next leader began all-out campaigning with a policy debate Saturday, and the hawkish front-runner Shinzo Abe won Prime Minister Junichiro Koizumi's endorsement.

Abe, chief Cabinet secretary in Koizumi's government, Finance Minister Sadakazu Tanigaki and Foreign Minister Taro Aso took part in the debate before giving their first joint public speeches in downtown Tokyo.

The three are members of the Liberal Democratic Party. The next party leader — to be chosen in a Sept. 20 party ballot — is virtually guaranteed of being elected prime minister by Parliament later this month because of the party's strong majority.

CountryWatch: Japan

Koizumi, who took office in April 2001, has said he will step down when his term as party president ends at the end of September. But he had not previously endorsed anyone as his successor.

"I will cast my vote for Mr. Abe," Koizumi told a group of reporters Saturday during his visit in Helsinki, Finland to attend the Asia-Europe Meeting. "Since I became prime minister, Mr. Abe ... has been the closest to me and helped me move ahead with reforms."

Abe "has done a superb job and earned recognition as a future leader," Koizumi said.

During the policy debate at LDP headquarters, Abe said Japan's economy will benefit if the country more aggressively promotes free trade across Asia, where China is moving ahead in signing deals.

"By promoting free trade and economic cooperation, we can pump up Asia's economic growth to benefit Japan's growth," Abe said. "If we keep up the effort, there is still room for Japan's economic growth."

The candidates later took to the streets for joint campaign speeches in Tokyo's Akihabara district — the first of five similar events — vying with each other before nearly 10,000 supporters and weekend shoppers.

Abe renewed his calls Saturday for Japan to build a stronger military and to push ahead with economic reforms. He also reiterated his intention to revise Japan's U.S.-drafted 1947 pacifist Constitution, which renounces the use of force in settling international disputes.

"I seek to draft a constitution of our own that fits Japan in the 21st century," Abe said. "I represent the postwar generation ... and I will get the plan going as part of a political schedule."

Abe, 51, known for his assertive stance toward China and North Korea, said he will seek to improve relations with Japan's Asian neighbors, and pledged to preserve Japan's alliance with the United States.

"By keeping close the Japan-U.S. alliance, we can contribute to the peace in Asia and elsewhere in the world," Abe said.

Koizumi's annual visits to a Tokyo war shrine, which honors Japan's 2.5 million war dead, including convicted war criminals, have strained ties with China and South Korea. Both countries suffered atrocities by Japan's wartime army and both have suspended summits with Koizumi in protest.

Abe vowed to try to resume talks with Chinese and South Korean leaders.

"It's important that both of us make efforts," Abe said. "We need to bare our chest and talk to each other, especially when there are problems."

Abe also has worshipped at Yasukuni Shrine many times and has backed Koizumi's visits. But he hasn't said whether he would visit if he becomes prime minister.

During the public speech, Abe also promised to resolve the issue of North Korea's abduction of Japanese nationals, the issue that boosted his profile and popularity.

Tanigaki, who has criticized Koizumi's Asian diplomacy and opposed the shrine visits, is presenting himself as the candidate with economic credentials who could also mend Japan's foreign relations.

"If Japan continues to remain a leader in Asia, we must be considerate to the feelings of our neighbors, not just those of the Japanese," Tanigaki said.

Aso did not address the shrine issue and focused on a need for economic reforms and the defense alliance with Washington. A comic book enthusiast, Aso emphasized the importance of keeping up with the Japanese specialty of animation, an obvious appeal to "otaku," or "geek" voters.