this level avoids the danger of a misplaced sacrifice In certain competitive situations, vulnerability can influence the optimum contract. Thus, with the HCP evenly split and facing a bid at the three level by the opposition, bidding to a level above the number of trumps held can be a useful sacrifice at favourable vulnerability. Examples For example, suppose that North-South have an eight-card heart fit and East-West have an eight-card spade fit. The total number of trumps is 16 so the "law" says the total number of tricks is also 16. That is, if North-South can take eight tricks playing in hearts, then East-West can take 16 - 8 = 8 tricks playing in spades; if North-South can take nine tricks in hearts, LoTT says East-West can take only seven tricks in spades. In the diagram, N-S have 9 spades and E-W 8 hearts combined. N-S can make 4 spades (conceding two clubs and heart ace) while E-W can make only 1 heart on a good defense (which takes a trump from QJ, two spades, diamond ace and two diamond ruffs)—the law holds, as the total tricks available is 10+7=17. Note, however, how minor card rearrangements affect the law: Consequences There are a number of bridge conventions that take advantage of this principle. For example, Bergen raises following an opening bid of one of a major (using a 5-card major system): 3 of the major = 4-card support and 0-6 HCP 3C = 4-card support and 7-9 points 3D = 4-card support and 10-12 HCP In 2002, Anders Wirgren called the accuracy of the "law" into question, saying it works on only 35-40% of deals. However, Larry Cohen remains convinced it is a useful guideline, especially when adjustments are used properly. Mendelson (1998) finds that it is "accurate to within one trick on the vast majority of hands" References Cohen, Larry (1992). To Bid or Not to Bid: The LAW of Total Tricks. Natco Press. . Jabbour, Zeke (August, 2004). Lawless Territory. ACBL Bridge Bulletin, pp. 27–28. Mendelson, Paul (1998). Mendelson's Guide to The Bidding Battle. Colt Books, Cambridge, UK. Jean-René Vernes, "The Law of Total Tricks" in The Bridge World "http://www.newbridgelaw.com/ "I Fought the Law of Total Tricks", Wirgren, Anders Contract bridge bidding