At the 2016 Rio Olympics, Japan's 4×100m sprint relay team stunned the world when they clinched the silver medal. With World Championship 4×100m bronze medalist Kenji Fujimitsu, we explore the secrets behind Japan's unique baton exchanges, which first propelled them to a medal at the 2008 Beijing Games. We take a closer look at the skill involved in the risky underhand or "up-sweep" baton pass technique, and discuss why the Japanese team originally decided to adopt this difficult approach.