Rubber bridge is a form of contract bridge played by two competing pairs using a particular method of scoring. A rubber is completed when one pair becomes first to win two games, each game presenting a score of 100 or more contract points; a new game ensues until one pair has won two games to conclude the rubber. Owing to the availability of various additional bonus and penalty points in the scoring, it is possible, though less common, to win the rubber by amassing more total points despite losing two games out of three. Rubber bridge involves a high degree of skill but there is also a fair amount of luck involved in who gets the best cards. A popular variation of rubber bridge is known as Chicago.