By Siobhan Robbins, South East Asia correspondent
At one of the most militarised borders on Earth, it was undoubtedly an historic handshake.
The world watched as a North Korean leader offered a US president an extraordinary invitation to cross the border.
Donald Trump didn't hesitate – not just stepping, but positively striding into the history books as the first sitting American president to meet a leader in the North since the end of the Korean War in 1953.
In terms of optics, this was a triumph for both leaders.
The lengthy handshake in North Korea was political capital for Chairman Kim, ensuring both men had a win to show their people as they boldly recrossed the border.
"It is a great day for the world," Kim Jong Un declared. "I believe that just looking at this action is an expression of his [Donald Trump's] willingness to eliminate all the unfortunate past and open a new future."
The US president was also full of flattery – after a year of negotiations, it seems the unpredictable pair have learned what makes the other tick.
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Mr Trump enthused: "I just want to say that this is my honour. I didn't really expect it, we were in Japan for the G20 we came over and I said 'hey I'm over I want to talk to Chairman Kim'.
"And we got to meet and stepping across that line was a great honour, a lot of progress has been made. A lot of friendships have been made and this, in particular, a great friendship. I just want to thank you, that was very quick notice and I want to thank you."
And quick notice it was – a spur of a moment invitation offered by tweet and responded to in record time by Pyongyang.
If nothing more, Mr Kim's decision not to stand up Mr Trump shows he believes there is still something to gain from diplomacy, and the president thanked him for the courtesy.
"If he didn't show up, the press was going to make me look very bad. So you made us both look good and I appreciate it," the president half-joked.
After February's failed Hanoi summit and stalling relations, today's meeting was no doubt also a relief for the watching South Korean President, Moon Jae-in, the long-suffering political matchmaker in this union.
What was billed as being a quick handshake extended to about 50 minutes, ending with an impromptu news conference where Donald Trump boasted about the progress made.
He said: "We've developed a great relationship. I really think that if you go back two-and-a-half years and you look at what was going on, prior to my becoming president, it was a very, very bad situation, a very dangerous situation for South Korea, for North Korea, for the world."
On one hand, he's right – the current diplomatic approach to the problem is a huge step forward from the "fire and fury" insults of 2017 when many analysts feared the region could be on the brink of war.
But despite Mr Trump's claims, the danger hasn't passed.