Updated

For nearly two decades, small-time smugglers worked the secret trails and quiet river crossings of the China-North Korea border, helping knit North Korea to the outside world by bringing in everything from food to South Korean soap operas.

But the rise of the young ruler Kim Jong Un is echoing on those secret trails, with his surging weapons tests leading to tighter international sanctions and leaving a few well-connected, highly sophisticated Chinese businesses controlling much of the frontier's trade — legal and otherwise. That is bad news for the small-time smugglers.

In rare detailed interviews, nearly a dozen people tied to those smuggling networks say their world has been thrown into turmoil in the years since Kim came to power.