Harvard quickly took a liking to the rugby game, and its use of the try which, until that time, was not used in American football. The try would later evolve into the score known as the touchdown. On June 4, 1875, Harvard faced Tufts University in the first game between two American colleges played under rules similar to the McGill/Harvard contest, which was won by Tufts. The rules included each side fielding 11 men at any given time, the ball was advanced by kicking or carrying it, and tackles of the ball carrier stopped play. Further elated by the excitement of McGill's version of football, Harvard challenged its closest rival, Yale, to which the Bulldogs accepted. The two teams agreed to play under a set of rules called the "Concessionary Rules", which involved Harvard conceding something to Yale's soccer and Yale conceding a great deal to Harvard's rugby. They decided to play with 15 players on each team. On November 13, 1875, Yale and Harvard played each other for the first time ever, where Harvard won 4–0. At the first The Game—the annual contest between Harvard and Yale, among the 2000 spectators attending the game that day, was the future "father of American football" Walter Camp. Walter, who would enroll at Yale the next year, was torn between an admiration for Harvard's style of play and the misery of the Yale defeat and became determined to avenge Yale's defeat. Spectators from Princeton admired this type of game and it became the most popular version of football there.