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
Contract bridge the round; otherwise, they receive penalty points. Bridge extends the concept of bidding into an , where partnerships compete to take a , specifying how many tricks they will need to take in order to receive points, and also specifying the trump suit (or no trump, meaning that there will be no trump suit). Players take turns to call in a clockwise order: each player in turn either passes, doubles—which increases the penalties for not making the contract specified by the opposing partnership's last bid, but also increases the reward for making it—or redoubles, or states a contract that their