DANDONG, Oct. 16 -- The first trucks across the New Yalu River Bridge on Thursday were wrapped in flowers and flanked by North Korean flags. What they carried, and how many will follow, neither government has said.

The four-lane crossing between Dandong and the North Korean city of Sinuiju opened to traffic after a joint ceremony, Xinhua reported, four months after Xi Jinping's Pyongyang summit reset the neighbours' relationship.

Capacity is the point. Xinhua said the older Yalu River Bridge, a combined road and rail crossing, took trucks of no more than 20 tonnes and allowed road traffic in one direction only. The new cable-stayed span has a 28.5-meter-wide deck with four lanes for two-way traffic and clearance for vessels of up to 3,0...