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 six, so a bid must be between one (seven tricks) and seven (thirteen tricks). A bid is higher than another bid if either the level is greater (e.g., 2 over 1NT) or the denomination is higher, with the order being in ascending order: , , , , and NT (no trump). Calls may be made orally, or with a bidding box, or digitally in online bridge. If the last bid was by the opposing partnership, one may also the opponents' bid, increasing the penalties for undertricks, but also increasing the reward for making the contract. Doubling does not carry to