Photos: See Chloe Kim and Shaun White in Snowboarding Halfpipe

Snowboarding’s halfpipe competition has begun at the Beijing Winter Olympics. In a sport where a bad run can knock athletes out of contention, and a bad fall can do far worse, every run matters, even in the qualifying round.

Chloe Kim, the defending gold medalist from the United States, delivered as needed on Wednesday. She scored a 87.75 in her first of two runs, guaranteeing her a spot in Thursday’s final. The men’s qualifying runs are now underway, with all eyes on Shaun White, who is competing in his last Olympic Games. He fell on his first run, with one run to go.