After warm greetings and a "social dinner", US President Donald Trump and North Korean leader Kim Jong Un get down to business Thursday, with formal summit talks aimed at breaking the deadlock over Pyongyang's nuclear programme.
The two men who once traded personal insults and threats of destruction are holding their second meeting in eight months, with analysts warning it needs to produce more substance than their initial historic get-together in Singapore.
That summit resulted in warm images but only a vague commitment from Kim to "work toward complete denuclearisation of the Korean peninsula".
Diplomacy has since stalled amid disagreements on what that actually means.
In Hanoi, the two again displayed outward signs of an unlikely diplomatic bromance, clasping hands and appearing to share jokes as reporters shouted questions.
Trump described Kim as a "great leader" and said his country had "tremendous economic potential, unbelievable, unlimited" as he vowed to "help" North Korea achieve those goals.
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In return, Kim appeared to have been counting the days until he saw Trump again.
"We came all the way to Hanoi to meet again, 261 days later," he told the US president, vowing to do his best to ensure a "great outcome" from the talks.
The pair then enjoyed an intimate dinner with just their closest aides and again beamed for the camera, Trump touting their "special relationship".
It was a far cry from the height of missile testing tensions in 2017 when Trump slammed Kim as "rocket man" and the younger man branded the US president a "mentally deranged US dotard".
Analyst Daniel Davis, Senior Fellow at Defence Priorities, said: "When you look at from where we were in December 2017, when we were literally on the brink of potential war... we're moving in the direction of peace and nobody's even talking about war right now."
"North Korea should learn from Vietnam."