Former Liberal Democratic Party lawmaker Shintaro Ishihara is determined to run in the April 11 Tokyo gubernatorial election and is expected to announce his candidacy today, political sources said Tuesday.

Ishihara is considered another prominent choice among conservative voters. The ruling Liberal Democratic Party is supporting Yasushi Akashi, 68, a former United Nations undersecretary general, while former Foreign Minister Koji Kakizawa, 65, and noted political scientist Yoichi Masuzoe, 50, have also entered the race.

Others planning to join include education critic Mitsuru Mikami, 66, and Kunio Hatoyama, 50, former vice president of the Democratic Party of Japan.

Former Upper House member Chimpei Nozue has withdrawn from the race and given his backing to Masuzoe.

Ishihara's bid is likely to trigger more turmoil in the LDP, whose ranks were split by Kakizawa's insistence on running against the party's wishes. The LDP expelled him Monday.

Ishihara, a 66-year-old writer-turned-politician, is a popular figure. He won the Akutagawa Award, the nation's most prestigious literary prize, in 1956 for his novel "Taiyo no Kisetsu" (Season of the Sun).

He entered national politics with his election to the Lower House in 1968. Later, he switched to the Upper House and served as Environment Agency chief and transport minister before leaving national politics in 1995.

Ishihara is also known as coauthor of "The Japan That Can Say No," a bubble-era book that suggested Japan take a nationalistic posture in its international relations.

It would be Ishihara's second challenge for the governorship of the nation's capital since 1975, when his 2.33 million votes failed to beat then-incumbent Ryokichi Minobe. Ishihara has maintained an interest in governing Tokyo ever since.

Coming out of his office in Tokyo's Azabudai district Tuesday evening, Ishihara told reporters "I will hold a news conference tomorrow. No one would do that if you weren't entering the race."

While the possibility that Ishihara might enter the race has been floated recently, he has maintained his silence and kept political circles in suspense.

Some observers said Ishihara's strategy is to draw as much attention as possible before entering the race. Many LDP Diet members, including his son Nobuteru, and Koki Kobayashi, would support Ishihara if he jumped in, political sources say.

Takeo Hiranuma, a Lower House member who visited Ishihara at his office Tuesday afternoon, told reporters, "I came here to encourage him ... He said that all the decks had been cleared and that he would just make his utmost efforts."

Touching on the LDP's split ranks, Chief Cabinet Secretary Hiromu Nonaka told a press conference Tuesday he feels sorry for Akashi, who sacrificed his job (as the head of the Hiroshima Peace Institute) to run for governor. "We must avoid (the notion) that there is a party but no rules to respect," said Nonaka, implying the party would take a strong stance against those who defy party decisions.