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 placed over the bidding cards attaching to the box base. A bridge auction consists of a sequence of "calls" (a bid, pass, double, or redouble) made by each player in turn, until it is concluded by a sequence of three consecutive passes. With the transition from auction bridge to modern contract bridge, the bidding has become more complex, and conventional auctions often last through several rounds of bidding. Such long auctions are hard to memorize and review. In addition, oral bidding causes noise in tournament halls, and auctions can be easily overheard at the other tables. Bidding boxes were invented