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
Law of total tricks contract. It is of most value in competitive bidding situations where the HCP are divided roughly equally between the partnerships. LoTT is said to be most accurate when the HCP are fairly evenly divided between the two sides and the bidding is competitive. Experts apply adjustment factors to improve accuracy. Payne and Amsbury's "Bridge: TNT and Competitive Bidding" (1981) may have been the first major book on the topic. In the introduction, the authors acknowledge Jean-René Vernes as the first writer to investigate TNT (Total Number of Tricks) Theory. Page 19 includes a key table that may not have been