For Xi, having Kim under his wing could increase leverage in his dealings with Trump amid the escalating trade war between the USA and China. More than 36,500 USA troops died in the conflict.
Punggye-ri has been the staging ground for all six of the North's nuclear tests, including the latest and by far most powerful one in September past year which Pyongyang said was an H-bomb.
The remains are likely to be brought to Osan, a US military air base south of Seoul, before being sent to Hickam Air Force Base in Hawaii for identification. Among the techniques they could use are detective work with old photos, comparing DNA from remains to that of missing soldiers' relatives and analysis of dental work.
The decision has brought harsh criticism that the USA made a concession without securing concrete measures and a road map for complete, verifiable and irreversible denuclearization of the North.
The transfer of remains is usually done in a somber, formal ceremony, and that is what officials said was being planned.
Uncertainty for Erdoğan as Turkey awaits election results
Ballots for Turkey's presidential and parliamentary elections are pictured at a polling station in Yalova, Turkey June 24, 2018. If a candidate wins just over 50 percent of the vote, he will win the presidency, but if not, there will be a runoff on July 8.
Trump said at a Cabinet meeting in the White House that "They've stopped the sending of missiles, including ballistic missiles".
The degree that bones have broken down is also important, and deterioration, such as from being under soil, can affect whether DNA can be recovered, he said.
Now that North Korea and China have achieved one of their long-cherished goals, they might move toward the next step - easing the harshest-ever sanctions imposed on the Kim regime over its nuclear and missile provocations.
Government and military officials in South Korea said Friday that the return of the remains is expected to take a significant amount of time given how many there are and that various ideas about the method of repatriation are being mulled.
Regardless of the positivity or negativity of post-summit analyses and reports, the hosting of the event has affirmed that the sources of "soft power" that Singapore tapped are manifold even if the country is limited by the size of its population as well as its lack of natural resources.
It was Kim's third visit to China in three months and appears to have sent a strong message to the United States: China remains a key player in negotiations toward denuclearization. With Xi standing behind him, Kim could also believe that he would have a stronger negotiating position vis-a-vis the US.
"Again and again the USA has been provoking a trade war".