Contract Bridge evolved slowly from the game of Whist, through the games of Auction Whist, Auction Bridge and finally to Contract Bridge in 1926. It differed from its predecessors in that only tricks bid for and made counted towards game (based on the Plafond system).
Harold Vanderbilt changed considerably the method of scoring and perfected the new game with the inclusion of incentives for games and slams, as well as the Plafond system of bidding towards game by accumulating partscores.