In a country consumed by conflict, a sport defined by brutality dominates: Myanmar’s lethwei martial art, where headbutts are encouraged and knockout blows are the aim of the game. “I can’t live without fighting,” said 19-year-old Su Luck, who enters the ring under the paradoxical pseudonym “Peace Prize”. “I have never once considered giving up this passion,” she said. Lethwei is traditional Burmese boxing, distinct from Thai kickboxing because head blows are permitted and fighters compete...