Mr. Kim and his colleagues have lunch at a restaurant in Dandong, China. (Yoonjung Seo /for The Washington Post)

It wasn’t so much that Mr. Kim was unhappy with the food. It was fine, if not great. But he needed to assert himself as a customer who shouldn’t be messed with.

“This needs ground sesame seeds,” he said to the clearly unimpressed Chinese cook, who had been summoned so Kim could complain about the kongbiji, a soft tofu dish, on the table.

He also sent back a plate of raw, marinated crabs, all cut in half and peppered with small pieces of chili, and instructed that steamed crab should be brought out instead.

“With Chinese, you’ve got to complain a bit from the beginning, be strong with them,” said Kim, who did not want his full name used, over lunch with his colleague (who also went by the name of Mr. Kim), as well as some business counterparts and two foreign reporters on a recent day.

It’s a philosophy Kim lives by in his day job as a North Korean businessman working in China. North Korea may be dependent on its huge, powerful neighbor, but that doesn’t mean it should just take whatever China gives.

Kim is part of the economic lifeline that is keeping North Korea afloat. He manages a factory in a small town outside Dandong, China’s commercial gateway to North Korea, where North Korean women work making clothes for a Chinese company. The women are allowed to keep one-third of the $300 a month they earn, while the rest goes back to Kim Jong Un’s regime in Pyongyang.

Since Kim Jong Un succeeded to the leadership of North Korea three years ago, he has dramatically increased the use of labor as a tool to earn foreign currency. Experts estimate that about 50,000 North Koreans are now working abroad in labor compounds like Mr. Kim’s factory, with 13,000 of them here in the Dandong region.

The West likes to think of North Korea as an isolated Hermit Kingdom, but the reality is that businessmen like Kim are leading normal lives in neighboring China, going about their business freely and thinking up ways to make more money for the regime.

This kind of economic activity is, however — like so much of what North Korea gets up to — happening off the United States’ radar.

But Kim recently gave two Washington Post reporters a revealing glimpse of how he operates in China, showing them around his factory and letting them read through orders sent from Pyongyang, allowing them into the dormitories where the women eat and sleep, and even letting them chit-chat with the women.

With his talk of profit margins and ambitions for global expansion, Kim could have been any big-talking businessman anywhere.

Then, over a two-hour lunch, he expounded on his theory of how to do business — but not before he’d dealt with the food.

In a private room in a small restaurant here, the low table soon became overloaded with food: cow’s stomach with pickled vegetables, clams in clear soup, steamed crabs, potato pancakes, noodles, soft tofu, cold cuts, spicy fish — and a small bowl of sesame seeds.

All of it was washed down with a Chinese firewater that tasted slightly better than its name in English, Black Soil, implied, along with repeated toasts of “Happy new year” and “Nice to meet you.”

Puffing away on Chinese cigarettes, sitting on a small plastic stool with his iPhone on the table in front of him, Kim surveyed the food. When the waitress brought out the side dishes, Kim commented that they all looked tasteless.

“This is nothing compared to North Korean kimchi,” he said, jabbing at the pickled cabbage that is present at every Korean meal. “If you’ve ever had North Korean kimchi, you’d know that this is no good.”

Kim was proud to be North Korean and, like many Koreans the peninsula over, looked down his nose at the Chinese.

His message, in business and in his daily life here, seemed to be: You’ve got to show them who’s boss.

Considering that North Korea has few friends in the world — and even the friends it has don’t like it very much — Kim was staking out a gutsy position. But it’s a tactic that the regime back home has been using to its advantage for years: You may have a weak hand, but you can play it well.

Still, Kim played down the recent political tensions between China and North Korea, which have had people in Washington hoping that Beijing is bringing its pressure to bear on the regime next door.

“It looks like South Korea and China are close now, but this is just China being strategic,” Kim said. “The Chinese know that the only way to stop American bastards from coming to China is to manage South Korea and North Korea,” he said, using the word often used in North Korean propaganda for U.S. officials. “China hates America, and so does North Korea. Why wouldn’t the world hate America?”

But Kim had little interest in political talk, and the discussion turned to matters more familiar.

How was his wife finding life in China? Kim, in his early 50s, sucked his teeth. He had visited China many times before, but for his wife it was a new experience. And, as the matron of the clothing factory, she had no peers here.

“Women have this illness, they need to talk all the time,” he said, tapping his cigarette ash into the crab shells lying on the table in front of him. “My wife doesn’t have any people here to talk to, so when I get home all she wants to do is chat, chat, chat. I just turn up the volume on the TV,” he said, pretending to have a remote control in his hand.

As for his children, his daughter, who had been a teacher, was about to give birth to their first grandchild, a boy. Kim did not seem particularly excited about the prospect, instead complaining about her husband — too short — and taking the opportunity to lament her career choices.

He complained that she studied too much and always had her nose in a book. He wants her to become a Workers’ Party member so she can be a trader like him and go out to make money.

“That’s where the future is,” he said.

Throughout the lunch, Kim’s colleague and a Korean-Chinese businessman had been having their own conversation at one end of the table, hashing out ideas for a new venture, breaking into the main discussion only to remonstrate a reporter for toasting with water in place of the clear liquor.

But at Kim’s hopes for his daughter, his North Korean colleague interjected: “You capitalist!” This prompted peals of laughter and an exhortation to have another drink.

Then it was time for Kim to go back to his factory, back to the decidedly uncommunist pursuit of making as much money as possible.

Yoonjung Seo contributed to this report.

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