The quadruple axel — a 4½ rotation jump — has never been completed in competitive figure skating.
It’s a demanding feat, requiring strength, poise, stamina and confidence. It is one of the very few remaining challenges for Japanese figure skater Yuzuru Hanyu, who retired from competitive skating this week after an extraordinary career. He is considered one of the greatest figure skaters ever, and his departure leaves a gaping hole in the sport. It will be filled eventually, but he will be missed.