Kim Jong Un on Friday became the first North Korean ruler to cross the border into South Korean territory since 1953 as he met with President Moon Jae-in. The one-day bilateral summit is the third ever meeting between leaders of the two Koreas, but skepticism is high about whether they can achieve any concrete progress on denuclearization. The face-to-face meeting has been heralded as a diplomatic win following years of the North's repeated nuclear tests and missile launches. But many believe Moon will use Friday's summit to establish trust rather than broach the nitty-gritty details of the North's nuclear program. The event's real purpose, according to strategists, is to set the stage for Kim's meeting with President Donald Trump slated for May or June. The two leaders discussed denuclearization in Friday's morning session, Reuters reported, citing a South Korean official. Without making Pyongyang denuclearize, "we cannot open a new chapter of peace on the Korean Peninsula," Moon Chung-In, special advisor to the South Korean president, told CNBC's Chery Kang, adding that denuclearization was certainly on Friday's agenda. "We are hoping to have peace settlements and an improvement of inter-Korean relations, they are all tied up into the issue of North Korea's nuclear problem," he continued.

Main takeaways from Moon-Kim summit

The two leaders are expected to sign a joint agreement at the close of Friday. Close attention will be paid to wording and potential promises Kim may make regarding matters of inter-Korean cooperation, such as family reunions, as well as nuclear policy. The special advisor to President Moon said his country was hoping to persuade Kim "to adopt a joint statement on the denuclearization of North Korea," adding that "it is very important for us to get a written statement." But such a statement is likely to be general, experts said. "It's kind of going to be like a very short-term sheet," said Jasper Kim, director of the center for global conflict management at Seoul's Ewha University. Details on denuclearization may only be fleshed out at the Trump-Kim summit, he continued. "The success metric for [Friday] should be the establishment of trust, number one. And, number two, a broad-based agenda," the professor stated. The third-generation North Korean leader came to Friday's summit to put an end to the history of the Korean conflict, Reuters reported, citing an official.

North Korea has traditionally reserved denuclearization as an issue to be exclusively broached with the United States Scott Snyder Council on Foreign Relations

While President Moon, who has been criticized for being too accommodative to Pyongyang, isn't expected to take a hard-nosed stance towards Kim, he's not likely to be soft either. Seoul "is under some pressure because Donald Trump has been stressing, with the likes of John Bolton, to get results quickly out of this summit process," said Chad O'Carroll, managing director of Korea Risk Group. "Compared to previous summits where there would have been a lot more discussion on incremental steps, Moon will be coming in from the position that the U.S. needs to see some very clear progress on denuclearization," O'Carroll added. Pyongyang is also aware of those dynamics, so "there may be potential for surprises that analysts may not have expected from the North Korean side," he concluded.

North Korean leader Kim Jong Un and South Korean President Moon Jae-in shake hands at the Inter-Korean Summit April 27, 2018 in Panmunjom, South Korea. Korea Summit Press Pool/Getty Images

Kim may save nuclear talks for Trump