BEIJING: China will open a high-speed rail line to the North Korean border on Tuesday, state news agency Xinhua said, the latest effort to boost economic ties despite tension between the countries. The line, under construction since 2010, will run 207 km (127 miles) from Shenyang to the border city of Dandong, which faces North Korea across the Yalu River, and will shorten the train journey from three-and-a-half hours to just over one hour, Xinhua said. As much as 80 per cent of trade between China and North Korea passes through Dandong.