For decades, China powered spectacular growth through exports, infrastructure and cheap credit. But that old model is running out of steam, even as it hits a record trade surplus with the world this year.

The property sector is drowning in debt, confidence is fading, and consumers are holding back. Now, Beijing faces its toughest test yet: how to keep the world’s second-largest economy growing without relying much on the engines that once drove it.

A new five-year plan promises “high-quality growth” built on technology and self-reliance. But trade tensions with the United States could make the climb even steeper.