The date of local Japanese participation in the sport is most frequently cited as 1899, when students at Keio University were introduced to the game by Professor Edward Bramwell Clarke (who was born in Yokohama) and Ginnosuke Tanaka (田中 銀之助). Both Clarke and Tanaka were graduates of Cambridge University. Japanese rugby only started to grow in the 1920s. Clarke taught English and coached rugby union at Keio from 1899 to 1910, after which an injury to his right leg forced him to give up playing.