The sushi chef was leaving his apartment when he noticed the stranger outside. He could tell by the man's suitblack and badly madethat he was North Korean. Right away, the chef was nervous. Even in his midsixties, the chef is a formidable man: He has thick shoulders, a broad chest; the rings on his strong hands would one day have to be cut off. But he'd long since quit wearing his bulletproof vest, and the last time a North Korean made the journey to visit him in Japan, a decade ago, he was there to kill him.

The stranger came closer. It was a warm day in June 2012. The chef lives in the Japanese city of Saku, a characterless, remote town filled with strip malls and rusting construction equipment. It's a place where apartments are cheap and anonymous, which suits the chef just fine. The light was glaring off the peaks of distant Mount Asama. They both wore sunglasses.

"This is about your family," the stranger said. "And somebody who wants to see you."

"Go away," the chef told the man, and without another word the man disappeared.

A month later, in early July, another North Korean in a black suit came to the chef's door. The chef recognized the man from the exclusive parties thrown for Kim Jong-il and his entourage in the years before the chef had escaped the Dear Leader and returned to Japan.

"Come with me, Fujimoto," the man said, and together they went to a bare-bones hotel near the Sakudaira train station. There the man handed the chef a red cloth. When he unfolded the fabric, he discovered it contained an invitation to lunch, in Pyongyang, with the new North Korean leader, Kim Jong-un. There was also a personal note from the new leader himself, which read, "You must fulll your promise to me. Return to Pyongyang. I will guarantee your safe passage."

Luring people back to North Korea to be executed or dispatched to gulags was a favorite trick of the regime. Fujimoto himself had seen it happen, and he remembers thinking at this moment, I, too, might be purged if I go again to North Korea.

But while the chef had run from Kim Jong-il, he had a soft spot for his son. "I was his playmate from when he was 7 to 18 years old," he recalled. "I said I would come back soon. That was a promise. I will come back."

Loyal to a fault, the chef packed his things and, later that day, bought a ticket for the same country he had so long ago escaped.

The chef's name, an alias, is Kenji Fujimoto, and for eleven years he was Kim Jong-il's personal chef, court jester, and sidekick. He had seen the palaces, ridden the white stallions, smoked the Cuban cigars, and watched as, one by one, the people around him disappeared. It was part of Fujimoto's job to fly North Korean jets around the world to procure dinner-party ingredientsto Iran for caviar, Tokyo for fish, or Denmark for beer. It was Fujimoto who flew to France to supply the Dear Leader's yearly $700,000 cognac habit. And when the Dear Leader craved McDonald's, it was Fujimoto who was dispatched to Beijing for an order of Big Macs to go.

When he finally escaped, Fujimoto became, according to a high-level cable released by WikiLeaks, the Japanese intelligence community's single greatest asset on the Kim family, rulers of a nation about which stubbornly little is known. We don't know how many people live there. (Best guess: around 23 million.) It's uncertain how many people starved to death during the famine of the late '90s. (Maybe 2 million.) Also mysterious is the number of citizens currently toiling their way toward death in labor camps, places people are sent without trial or sentence or appeal. (Perhaps 200,000.) We didn't even know the age of the current leader, Kim Jong-un, until Kenji Fujimoto revealed his birth date. (January 8, 1983.)