HONG KONG — In 2000, Kim Dae-jung, then South Korea’s president, flew to Pyongyang to meet with Kim Jong-il, the leader of North Korea — the first time talks had ever been held between leaders of the two sides.

The distance between the two airports was just 100 miles. But the flight took more than an hour, because the plane swung out over the sea west of the Korean Peninsula, to avoid crossing the heavily militarized land border.

On Friday, Kim Jong-un, Mr. Kim’s son and North Korea’s current leader, is expected to walk across that border, where he will be greeted by President Moon Jae-in of South Korea before they sit down for talks on the southern side of the Demilitarized Zone.

Friday’s talks, the third summit meeting between the Koreas, could produce a statement about pursuing a peace agreement to end the Korean War of 1950-53, which was paused by an armistice but never formally brought to a close.