Breaststroke is a popular and easy to learn recreational swimming style, but when it comes to top-level competition it's actually considered one of the most technically challenging of all. The effects of water resistance are particularly pronounced for breaststroke, meaning small adjustments can make a big difference. Down the decades Japanese swimmers have time and again set new standards for technique in the stroke. We meet Watanabe Ippei, the first man ever to record a sub-2m07s time in the 200m event, and assess his prospects for beating his formidable rivals on the world stage.