Contract bridge awards a bonus for holding a certain combination of high cards), although some are common between the two. A larger bonus is awarded if the declaring side makes a small slam or grand slam, a contract of 12 or 13 tricks respectively. If the declaring side is not vulnerable, a small slam gets 500 points, and a grand slam 1000 points. If the declaring side is vulnerable, a small slam is 750 points and a grand slam is 1,500. In rubber bridge, the rubber finishes when a partnership has won two games, but the partnership receiving the most "overall" points
Bidding box in 1962 in Sweden by Gösta Nordenson and first used at a World Bridge Championships game in Stockholm in 1970. Eric Jannersten, a Swedish social bridge player and founder of the largest European bridge equipment manufacturer, Jannersten Förlag AB bought the patent in 1970 being attributed by some as the inventor. However, the patent is disputed by the Swedish Bridge Federation. They quickly became popular in Europe, and after some resistance were accepted in American bridge clubs. , they are practically an indispensable part of the game, and even many rubber bridge players use them at home. Use of bidding