Tae kwon do
From Tardis Wiki, the free Doctor Who reference
"Tae kwon do" was an earth martial art often taught to schoolchildren and used in both athletic competition and self-defence.
Clara Oswald claimed to have taken tae kwon do lessons, though she didn't have much opportunity to demonstrate said abilities. (TV: Robot of Sherwood) She later took her Year Seven students for tae kwon do lessons, rendering her unavailable to join the Doctor on an adventure. (TV: The Woman Who Lived)
