Rugby was introduced to Japan in 1899. Edward B. Clark, an English instructor of Keio University in Tokyo and a former Cambridge University rugby player, taught Keio students how to play it. Today, rugby is primarily played by adult amateurs, and by college, and high school students. Rugby is probably more popular than American football in Japan. However, there is no professional rugby league. But several large amateur leagues and tournaments, held from December to March, gain considerable attention from Japanese sport lovers. These tournaments are the All Japan College Rugby Championship, the All Japan High School Rugby Championship, and the All Japan Rugby Championship. Both college and adult teams, or shakijin chimu, compete in the All Japan Rugby Championship. It determines the victor among the various Japanese rugby leagues.