China and Taiwan have begun the highest-level talks since the end of the Chinese civil war in 1949.
Wang Yu-chi and Zhang Zhijun, the top cross-strait officials from each side, are both attending the four-day talks in Nanjing.
No official agenda has been released for the talks, which are widely seen as a confidence-building exercise.
China regards Taiwan as part of its territory. In the past, all talks have gone via quasi-official organisations.
Speaking to reporters before departing from Taiwan, Wang, head of Taiwan's Mainland Affairs Council, said: "My main aim during this visit to the mainland is to promote mutual understanding between the two sides."
He added that he hoped the visit, which "did not come easily", would go smoothly, and said the two sides would not be signing any agreements during the talks.
Given the sensitivities, the meeting room had no flags on display, and the officials' nameplates had no titles or affiliations, AFP news agency reported.
Beijing insists that Taiwan is part of China and has a stated aim of reclaiming the island.
Taiwan still calls itself the Republic of China and nominally claims the same territory as the Communist government in Beijing, although it does not press these claims.
The US is committed to defending Taipei, despite not formally recognising Taiwan as an independent country.
The situation has created a decades-long military stand-off between Beijing and Washington.
But cross-strait ties have improved since Taiwan's pro-Beijing President Ma Ying-jeou was elected in 2008.
Cross-strait flights began in 2008, and tourists from the mainland have boosted Taiwan's economy.
Newspapers and experts in China and Taiwan are upbeat over the talks.
"Face-to-face talks will help dispel suspicion between the two sides, given that messages passed through the two organisations are sometimes misinterpreted," Ni Yongjie, deputy director of the Shanghai Institute of Taiwan Studies, tells the China Daily.
"The person responsible for cross-strait relations of both sides visiting each other and establishing a mechanism of communication confirms that the 'one-China framework' is beneficial for both parties in furthering understanding and deepening mutual trust…" writes People's Daily senior journalist Wu Yaming.
"There will certainly be some results following the meet, although it's uncertain in what form they will be made," Yang Lixian, analyst at the National Society of Taiwan Studies, tells the Global Times.
Taiwanese daily China Times says the current talks can address "practical issues" first and that can pave the way for a meeting between Taiwanese President Ma Ying-jeou and his Chinese counterpart Xi Jinping during the Asia-Pacific Economic Co-operation forum in November this year.
"There is no need for impractical fantasy of the outcome of the current meeting. It will be very precious if the meeting between Ma and Xi can be set up," says Taiwan's Apple Daily.
Trade agreements have allowed Taiwanese technology firms to expand massively, investing billions of dollars in the mainland.
However, Ma is unpopular and analysts say his governing Kuomintang party is likely to lose local elections later this year.
The talks are the first formal government-to-government dialogue since the 1949 split.
For years, mainland China and Taiwan dealt with each other indirectly, though so-called friendship associations and trade groups, the BBC's Celia Hatton in Beijing reports.
Amid all the smiles, tension remains: China refuses to retract its long-standing threat that it could eventually take back Taiwan, by force if necessary, our correspondent adds.
Taiwan negotiators are likely to propose the posting of permanent representatives on each other's territories.
But they will also face pressure to talk about press freedom after China refused accreditation to several media outlets.
"Press freedom is a universal value," Taiwan's Mainland Affairs Council said in a statement.
"We've repeatedly said that the most important thing regarding news exchange between the two sides is the free and equal flow of information."
Many Taiwanese are sensitive to issues of press freedom, having lived under a dictatorship that tightly controlled the media until the 1980s.
Correspondents say Beijing's negotiators are likely to press for closer economic co-operation.
The two sides are expected brief journalists at separate press conferences on Tuesday afternoon.