Some of those who have prepared Mr. Trump for dealing with Korea, who insisted on anonymity to speak about their briefings with the president, say they worry that he is so supremely confident in his negotiating skills that he has eschewed detailed briefings on how Mr. Kim thinks about the world.

When Mr. Trump said over the weekend that he would know “in one minute” after talking with Mr. Kim whether the North Korean was ready to denuclearize, it was a declaration that negotiating instinct, rather than deep study of the topic, was the way to success.

“Just my touch, my feel,” he said. “It’s what I do.”

The North Koreans have their own style of negotiating, too. When the United States was discussing an armistice to halt the 1950-53 Korean War, the chief North Korean delegate embarrassed his American counterpart by showing up for talks in the American ambassador’s car — which his invading troops had seized as they rampaged through Seoul at the war’s start.

The North Koreans had also secretly sawed several inches off the American delegate’s chair so their negotiator could look down on him during the haggling.

None of that gamesmanship is likely to happen Tuesday. But the opening minute may say a lot.

When Mr. Kim met the president of South Korea, Moon Jae-in, at the Demilitarized Zone in late April, he took his hand and guided him over into North Korean territory, an unexpected power play. There will be no equivalent border on Tuesday, but Mr. Kim will surely be looking to use whatever edge he can get.

And he has two primary sources of leverage: his newly acquired capabilities to put San Francisco, and maybe Chicago, within reach of his nuclear weapons, and North Korea’s longstanding ability to destroy Seoul with conventional artillery arrayed along the Demilitarized Zone.

While Mr. Kim may see utility in giving up some of those capabilities in return for economic benefits, he knows his nuclear arsenal is his best bet to stay in power.