Mr. Han has promoted the view that Taiwan and China belong to the same country, and had argued that closer ties with China would lift Taiwan’s economy. His tone has changed, however, in the wake of the recent wave of large protests in Hong Kong, where residents have demonstrated against a bill that would allow extraditions to mainland China and against police abuses during the protests.

In June, shortly after one of the biggest protest marches in Hong Kong, Mr. Han said that if he were elected president, Taiwan would only accept China’s “one country, two systems” proposal “over my dead body.”

Mr. Gou has been critical of the support Mr. Han has received from what many Taiwanese call the “red media,” or local news outlets that are more sympathetic to Beijing — led by those belonging to the Want Want Group, which has often been critical of the outspoken tycoon.

There has been widespread speculation that Mr. Gou may run for president as an independent. Although he appears to have lost convincingly to Mr. Han, the nature of the public poll, which also surveyed nonparty members, led to suspicion that supporters of Ms. Tsai had said they backed Mr. Han, viewing him as a weaker opponent for Ms. Tsai than Mr. Gou.

In addition to a possible independent bid by Mr. Gou, Taipei’s independent mayor, Ko Wen-je, may also announce his candidacy for January’s election. Should they both join the race, it would most likely benefit Ms. Tsai, since like Mr. Han they are seen as more China-friendly than Ms. Tsai, and would very likely split voters who favor closer ties with China.

Despite his victory, Mr. Han faces challenges within his own party, the Kuomintang. Having campaigned as the “president of the common people” who will help Taiwanese get rich — without offering details on how he intends to do so — he now needs to win over the party elite.

“Well-educated Kuomintang elites may not want to openly support Han,” Mr. Wang said. “He needs to focus on issues that those elites will want to work on with him.”