Japanese Prime Minister Junichiro Koizumi reshuffled his cabinet on Monday, setting up a battle among three leading candidates to replace him when his term expires next September.

Koizumi's most notable appointment was that of Shinzo Abe, 51, the acting secretary general of the ruling Liberal Democratic Party, as the new chief cabinet secretary -- a powerful job that includes the highly public post of top government spokesman. Abe, the grandson of a former prime minister, is considered a hawkish nationalist. He is a strong critic of North Korea and a leading proponent of Koizumi's controversial visits to Tokyo's Yasukuni Shrine, where Japan's war dead, including World War II criminals, are honored. The visits have outraged Japan's neighbors but sparked some nationalist support at home.

Koizumi also moved his minister for internal affairs and communications, Taro Aso, 65, to the higher-profile job of foreign minister. Aso is expected to work for the improvement of strained ties with China and South Korea over Japan's perceived lack of contrition for World War II-era atrocities. Japan also faces several increasingly bitter territorial disputes with its neighbors. Perhaps signaling the nationalistic tone of his upcoming tenure, Aso said bluntly on Monday that he would labor tirelessly for Japan's "national interests."

Koizumi also reappointed Finance Minister Sadakazu Tanigaki, 60, whom many have credited with helping reignite the world's second-largest economy. Tanigaki is considered more dovish than the two others and has avoided visits to Yasukuni. He is also thought to be among Koizumi's possible successors.

The reshuffle follows a landslide electoral victory for Koizumi in September that was widely interpreted as an endorsement of his crusade for bold economic reforms. Analysts said the new cabinet highlights the prime minister's desire to handpick an equally reformed-minded successor.

It also underscores Koizumi's competitive and trial-by-fire style, which has both shocked and captivated voters in a nation long accustomed to staid consensus politics. Indeed, Koizumi has suggested he will view the next several months as a period of battle among his potential successors, watching their performance so he can anoint the most competent.

"This is the administration to continue reform," Koizumi said at a news conference Monday evening. "Even after I leave in September of next year, I do not think that someone who diverges from Koizumi's reform policy will become the next prime minister."

Abe has been viewed by political insiders as the front-runner. But he has been criticized by some for being too openly hawkish, particularly on issues relating to Japan's desire for a more dominant global role. His new job as the nation's top spokesman will be a major test of his powers of diplomacy.

"Abe will have to give a press conference twice a day -- and he will have to learn to restrain his tongue on China and Korea," said Takao Toshikawa, editor in chief of the political newsletter Insideline.

Much had been made during the September elections of Koizumi's promotion of female politicians -- particularly Environment Minister Yuriko Koike, who some had said could eventually become Japan's first female prime minister. But by deciding keep her in her current job, rather than give her a more prominent cabinet post, Koizumi appeared to cross her off the short list of possible successors. Koizumi did, however, name another woman -- Kuniko Inoguchi, a politics professor who was elected to the lower house in September -- as the new minister in charge of gender equality and the falling birthrate.

Special correspondent Sachiko Sakamaki contributed to this report.

Shinzo Abe, 51, Japan's new chief cabinet secretary, is one of three main contenders to succeed Prime Minister Junichiro Koizumi.