The meeting was set up with unusual speed and great secrecy at the North's suggestion last week, the latest example of conflicting signals coming from Pyongyang that included an abrupt cancellation of an invitation for a US envoy to visit.
The North is likely to repeat its demand for the South and the United States to scrap the military drills, due to start later this month, but both sides have plenty of incentives to seek a deal that could break their long stalemate.
"For the North, if it comes back with an accomplishment in terms of improved South-North ties, it will mean a better atmosphere for Kim Jon Un to visit China and a justification to pursue high-level talks with the United States," said Cheong Seong-chang, an expert at the Sejong Institute outside Seoul.
Kim is believed to be seeking a visit to China, Pyongyang's greatest ally and main benefactor, to reinforce his legitimacy as leader. In his early 30s, Kim took power when his father died suddenly in 2010,
The South Korean delegation is led by President Park Geun-hye's deputy national security adviser. North Korea has sent the second-highest ranking official in the ruling Workers' Party department charged with ties with the South.