Contract bridge grand slam exists. The modern game of contract bridge was the result of innovations to the scoring of auction bridge by Harold Stirling Vanderbilt and others. The most significant change was that only the tricks contracted for were scored below the line toward game or a slam bonus, a change that resulted in bidding becoming much more challenging and interesting. Also new was the concept of "vulnerability", making sacrifices to protect the lead in a rubber more expensive. The various scores were adjusted to produce a more balanced and interesting game. Vanderbilt set out his rules in 1925, and within
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