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 tricks taken, the contract, and various other factors which depend to some extent on the variation of the game being played. Rubber bridge is the most popular variation for casual play, but most club and tournament play involves some variant of duplicate bridge, in which the cards are not re-dealt on each occasion, but the same deal is played by two or more sets of players (or "tables") to enable comparative scoring. For competition level, so called IMP score is of high significance. One theory is that the name "bridge" has its origins in the name of an earlier game.