A look at the two main candidates running in Taiwan's presidential election on Saturday.

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TSAI ING-WEN — A former law professor with a Ph.D. from the London School of Economics, Tsai is the candidate of the main opposition Democratic Progressive Party, which advocates Taiwan's formal independence and takes a skeptical view of its relations with China.

Tsai, 59, is running for the second time after being defeated by the incumbent, Ma Ying-jeou, in 2012. This year, she is leading by a large margin in most polls, putting her in a strong position to become Taiwan's first woman president.

Analysts say Tsai is a far stronger candidate this time around, partly because an earlier generation of DPP politicians have left the stage and are no longer competing for attention and influence. She's also seen as winning favor from the U.S. with a successful trip to Washington last year that contrasted with the somewhat frosty reception she received during the 2012 race.

Tsai served in the Nationalist Party administration of Lee Teng-hui, where she was one of the chief drafters of a policy redefining Taiwan-China relations as "special state-to-state" that enraged Beijing. She later served as head of the Mainland Affairs Council and vice premier in the administration of former DPP president Chen Shui-bian. She has also served twice as DPP chairwoman and help lead opposition to a major trade agreement with China that was ultimately passed by the legislature.

Tsai chose as her running mate Chen Chien-ren, 64, an epidemiologist and vice president of Academia Sinica, one of Taiwan's top research institutes.

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ERIC CHU — The candidate of the ruling Nationalist Party, Chu trained as an accountant and earned a Ph.D. at New York University. Like Tsai, he is the chairman of his party but only became its candidate for president in October following the jettisoning of Hung Hsiu-chu, whose strongly pro-China positions were seen as alienating voters.

Chu, 54, won a seat to the legislature in 1998, then was elected twice as head of Taoyuan county south of the capital Taipei. After Ma's 2008 election, Chu was appointed vice premier, becoming the youngest person ever to hold the job at the age of 48. He resigned to run in the 2010 race for mayor of New Taipei City surrounding the capital, defeating Tsai Ing-wen by 52.6 percent to 47.3 percent.

In the presidential race, Chu now lags behind Tsai in most polls by a substantial margin, partly as a result of the party's late-stage switching of candidates, but also due to voter concerns about the Nationalists China-friendly policies. Although Chu benefits from his image as a squeaky-clean technocrat, his candidacy is being dragged down by Ma's low approval ratings.

Though considered a moderate on unification, Chu led a delegation to Shanghai and Beijing last year that included a meeting with President Xi Jinping intended to portray the Nationalists as dependable custodians of the relationship. The trip was strongly criticized by the opposition and received a lukewarm public reception.

Like Tsai, Chu also made a visit to Washington, although the substance of his closed door meetings wasn't made public. Nationalist candidates have benefited in past from U.S. concerns over turbulence in the cross-strait relationship, although Washington has withheld endorsement of either candidate.

Chu picked lawyer and former minister of the Council of Labor Relations Jennifer Wang, 54, as his vice presidential candidate.