First, they embraced. Then South Korean President Moon Jae-in and his North Korean counterpart, Kim Jong Un, last month planted a tree and talked alone before committing their countries to denuclearization and further talks to bring a formal end to their conflict.
At the stroke of midnight in Seoul on Saturday (11 a.m. ET Friday), the goodwill continued, with North Korea adjusting its clocks 30 minutes forward to be in the same time zone as its southern neighbor.
North Korean state news agency KCNA called the moment "the first practical step taken after the historic third north-south summit meeting to speed up the process for the north and the south to become one."
The time change was ordered by decree of the Supreme People's Assembly, the news agency reported.
Another sign of the rapprochement will come next week, when a team from the UN's International Civil Aviation Organization will travel to North Korea to discuss a proposal to start an air route between the Pyongyang and Incheon, South Korea, airspace regions, according to Anthony Philbin, the agency's communications chief.
South Korean aviation officials are still weighing the proposal, which was requested by North Korea in February, Philbin said.
ICAO Asia and Pacific Regional Director Arun Mishra will travel to North Korea with the director of the agency's air navigation bureau, Stephen Creamer, to open discussion on air navigation and safety issues.
The heads of North and South Korea last month signed the Panmunjom Declaration for Peace, Prosperity and Unification on the Korean Peninsula during the first meeting between leaders of the two countries in 10 years. They committed themselves to the complete denuclearization of the Korean Peninsula and pledged to bring a formal end to the Korean War, 65 years after hostilities ceased.
In 2015, North Korea set its clocks back by 30 minutes to "Pyongyang time" on August 15 -- the 70th anniversary of liberation from Japan, KCNA reported then.
Time was reset as it was before Japanese colonization.
"The wicked Japanese imperialists committed such unpardonable crimes as depriving Korea of even its standard time," the state news agency reported.
North Koreans already have their own calendar. Instead of counting from the birth of Christ, they count from the birth of founding leader, Kim Il Sung. Kim was born in 1912.