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Different partnerships use different criteria for opening 1NT. One major difference is in opening 1NT with 5 card majors (see other section for data). The other is whether you have stopper or not. Opening with 5 cards major is a matter of preference and I happen to choose not to do so. I believe I can have a very complete system to handle 5 card major opening and would not want to include them in 1NT. I do not think there is any significant difference in the two approaches (assuming you use puppet Stayman to find 5 card major). Opening 1NT with some stopper requirement especially for the doubletons is another story. Some players insist that it is a good requirement for opening 1NT. My preference is to have no requirements. There is really no significant difference in the general strength of the 1NT opening whether you have stopper requirements or not. But stopper requirements will reduce the % of hands you will open 1NT from 4.9% to as low as 2.5% of your hands. If you do not feel secure enough, how about just requiring no 2 nonstop doubleton. Almost all 1NT hands satisfy this requirement. Here is some data form about 3.5 million random hands for those who want to look at (detail computer output is in the computer output section):- 1. no requirements on stoppers ( condition 1 in my program) percent for 1st hands is 4.914% ** best contract(NT or suit) average trick is 9.516 0 = 0.00% 0.00% 1 = 0.00% 0.00% 2 = 0.00% 0.00% 3 = 0.01% 0.01% 4 = 0.10% 0.11% 5 = 0.80% 0.91% 6 = 3.13% 4.04% 7 = 7.95% 11.99% 8 = 14.92% 26.91% 9 = 21.04% 47.95% 10 = 22.59% 70.54% 11 = 17.88% 88.42% 12 = 9.10% 97.52% 13 = 2.48% 100.00% This is for both not vul North south make 114223 67.05% 449.05 East west make 24192 14.20% -235.52 North south sac 13214 7.76% -137.61 East west sac 18733 11.00% 193.76 North south cannot make any contract = 4.04% East West cannot make any contract = 39.80% North south make partial contract = 43.52% East West make partial contract = 53.04% North south make any game = 40.86% East West make any game = 6.86% North south make any small slam = 9.10% East West make any small slam = 0.28% North south make any grand slam = 2.48% East West make any grand slam = 0.02% North south cannot make any NT contract = 24.77% East West cannot make any NT contract = 84.25% North south make partial NT contract = 32.88% East West make partial NT contract = 13.19% North south make NT game = 35.55% East West make NT game = 2.56% North south make NT small slam = 5.29% East West make NT small slam = 0.01% North south make NT grand slam = 1.51% East West make NT grand slam = 0.00% North south NT makes more then suit = 36.92% East West NT makes more then suit = 4.73% North south NT makes equal to suit = 3.94% East West NT makes equal to suit = 3.69% North south NT makes less then suit = 59.14% East West NT makes less then suit = 91.58%
2. Most strict requirement, must have A or KX or Qxx or xxxx in all suit (1 and 194) percent for 1st hands is 2.528% ** best contract(NT or suit) average trick is 9.510 0 = 0.00% 0.00% 1 = 0.00% 0.00% 2 = 0.00% 0.00% 3 = 0.01% 0.01% 4 = 0.12% 0.13% 5 = 0.91% 1.04% 6 = 3.22% 4.26% 7 = 7.92% 12.18% 8 = 14.96% 27.14% 9 = 20.84% 47.98% 10 = 22.33% 70.31% 11 = 18.04% 88.35% 12 = 9.29% 97.64% 13 = 2.36% 100.00% This is for both not vul North south make 60246 68.73% 447.68 East west make 11928 13.61% -224.37 North south sac 6234 7.11% -131.78 East west sac 9246 10.55% 191.64 North south make 65568 74.80% 584.06 East west make 16808 19.18% -239.59 North south sac 1354 1.54% -446.16 East west sac 3924 4.48% 696.64 North south cannot make any contract = 4.26% East West cannot make any contract = 40.92% North south make partial contract = 42.21% East West make partial contract = 52.92% North south make any game = 41.88% East West make any game = 5.96% North south make any small slam = 9.29% East West make any small slam = 0.20% North south make any grand slam = 2.36% East West make any grand slam = 0.01% North south cannot make any NT contract = 22.98% East West cannot make any NT contract = 84.72% North south make partial NT contract = 32.49% East West make partial NT contract = 12.81% North south make NT game = 37.78% East West make NT game = 2.46% North south make NT small slam = 5.37% East West make NT small slam = 0.01% North south make NT grand slam = 1.38% East West make NT grand slam = 0.00% North south NT makes more then suit = 38.33% East West NT makes more then suit = 4.81% North south NT makes equal to suit = 3.98% East West NT makes equal to suit = 3.76% North south NT makes less then suit = 57.69% East West NT makes less then suit = 91.43% 3. no two nonstop doubletons (condition 13) percent for 1st hands is 4.788% ** best contract(NT or suit) average trick is 9.513 0 = 0.00% 0.00% 1 = 0.00% 0.00% 2 = 0.00% 0.00% 3 = 0.01% 0.01% 4 = 0.10% 0.11% 5 = 0.81% 0.93% 6 = 3.15% 4.08% 7 = 7.98% 12.06% 8 = 14.94% 26.99% 9 = 20.97% 47.97% 10 = 22.59% 70.56% 11 = 17.86% 88.42% 12 = 9.12% 97.54% 13 = 2.46% 100.00% This is for both not vul North south make 111713 67.29% 448.54 East west make 23504 14.16% -232.89 North south sac 12645 7.62% -135.95 East west sac 18144 10.93% 193.45 North south cannot make any contract = 4.08% East West cannot make any contract = 40.02% North south make partial contract = 43.38% East West make partial contract = 53.03% North south make any game = 40.96% East West make any game = 6.68% North south make any small slam = 9.12% East West make any small slam = 0.26% North south make any grand slam = 2.46% East West make any grand slam = 0.02% North south cannot make any NT contract = 24.53% East West cannot make any NT contract = 84.29% North south make partial NT contract = 32.91% East West make partial NT contract = 13.16% North south make NT game = 35.78% East West make NT game = 2.54% North south make NT small slam = 5.29% East West make NT small slam = 0.01% North south make NT grand slam = 1.50% East West make NT grand slam = 0.00% North south NT makes more then suit = 37.08% East West NT makes more then suit = 4.74% North south NT makes equal to suit = 3.95% East West NT makes equal to suit = 3.72% North south NT makes less then suit = 58.98% East West NT makes less then suit = 91.54%
4. No nonstop doubleton ( condition 25) percent for 1st hands is 2.917% ** best contract(NT or suit) average trick is 9.471 0 = 0.00% 0.00% 1 = 0.00% 0.00% 2 = 0.00% 0.00% 3 = 0.01% 0.01% 4 = 0.14% 0.15% 5 = 0.93% 1.08% 6 = 3.43% 4.51% 7 = 8.26% 12.77% 8 = 15.27% 28.04% 9 = 21.08% 49.11% 10 = 21.99% 71.10% 11 = 17.34% 88.44% 12 = 9.23% 97.67% 13 = 2.33% 100.00% This is for both not vul North south make 68780 68.01% 444.88 East west make 14351 14.19% -221.18 North south sac 7215 7.13% -130.82 East west sac 10788 10.67% 195.61 North south cannot make any contract = 4.51% East West cannot make any contract = 40.43% North south make partial contract = 42.85% East West make partial contract = 53.39% North south make any game = 41.09% East West make any game = 5.99% North south make any small slam = 9.23% East West make any small slam = 0.18% North south make any grand slam = 2.33% East West make any grand slam = 0.01% North south cannot make any NT contract = 22.96% East West cannot make any NT contract = 84.76% North south make partial NT contract = 33.09% East West make partial NT contract = 12.79% North south make NT game = 37.16% East West make NT game = 2.45% North south make NT small slam = 5.37% East West make NT small slam = 0.00% North south make NT grand slam = 1.43% East West make NT grand slam = 0.00% North south NT makes more then suit = 39.25% East West NT makes more then suit = 4.63% North south NT makes equal to suit = 4.13% East West NT makes equal to suit = 3.58% North south NT makes less then suit = 56.62% East West NT makes less then suit = 91.79%
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