nige1 Posted December 24, 2018 Report Share Posted December 24, 2018 You have arrived in a good contract. The defence start with ace and king of clubs, followed by a third club won in hand with the queen (or won in dummy with the knave if you prefer?)..At IMPs, you take the safety play for one loser in trumps. What do you do at Match-point Pairs (mixed field)?I'm only criticising the use of a priori probabilities here, as if the probability of a 0-3 diamond break isn't affected by the fact that West passed throughout.Here are 100 hands dealt randomly on the condition that the NS cards are as above and West has ♠---♣AKx: West hands: 1. 2. 3. 4. - - - - 9 8 3 2 Q T 9 8 2 T 8 6 3 Q T 8 3 Q T 6 4 3 2 Q J T 6 2 J T 9 7 6 2 J 8 6 4 3 2 A K 5 A K 5 A K 2 A 6 2 5. 6. 7. 8. - - - - T 9 8 6 T 9 8 6 2 8 6 2 Q 9 8 6 Q 9 8 6 4 2 Q J T 9 2 Q T 9 7 6 4 3 9 7 6 4 3 2 A 9 2 A K 2 A 6 5 A 9 6 9. 10. 11. 12. - - - - Q T 3 2 Q T 6 2 T 8 6 2 Q T 3 J T 9 8 7 4 J T 9 7 6 2 Q J T 9 6 3 Q J 9 8 6 4 3 A K 2 A K 5 A 9 2 A 5 2 13. 14. 15. 16. - - - - Q 9 3 Q 9 3 2 Q 8 6 3 2 Q T 8 3 2 T 9 8 7 4 3 2 Q J T 9 6 3 Q J T 7 6 Q T 4 3 2 A 9 6 A 9 5 A 6 5 A K 9 17. 18. 19. 20. - - - - 9 8 3 2 T 9 8 6 2 Q 8 2 9 8 6 3 2 9 8 7 4 3 2 Q J T 7 6 Q T 8 7 6 4 2 J T 9 8 2 A K 2 A 5 2 A 9 6 A 5 2 21. 22. 23. 24. - - - - 6 2 Q 9 8 6 3 2 Q T 9 8 6 3 Q 8 J T 9 8 7 6 3 2 Q J T 7 Q J 6 2 Q J 9 8 7 6 4 3 A 9 6 A 6 2 A K 5 A K 6 25. 26. 27. 28. - - - - Q T 9 8 6 2 Q 6 2 Q T 3 2 Q T 2 J T 6 2 Q J 9 8 4 3 2 Q T 9 8 4 3 Q T 9 8 7 6 2 A 5 2 A 9 5 A 9 2 A K 9 29. 30. 31. 32. - - - - Q 9 8 6 2 Q 6 2 T 9 8 6 2 Q T 9 2 Q J 7 6 3 J 9 8 7 4 3 2 Q J T 8 4 J 9 8 7 3 2 A 6 2 A 5 2 A K 6 A 9 5 33. 34. 35. 36. - - - - Q 9 8 3 2 T 9 8 6 2 Q 9 3 2 9 6 3 J 7 6 4 3 Q T 7 6 2 Q J T 8 4 2 J T 8 6 4 3 2 A K 9 A 5 2 A 9 6 A 6 2 37. 38. 39. 40. - - - - Q T 8 3 2 Q T 6 3 Q 9 8 2 Q 6 3 2 Q J 6 4 3 J 9 7 6 4 2 Q T 8 6 4 2 Q T 9 4 3 2 A 5 2 A K 6 A 6 2 A 6 5 41. 42. 43. 44. - - - - Q 9 8 3 2 Q T 8 2 Q 9 8 6 9 8 6 3 2 Q T 8 7 3 Q J T 7 3 2 Q T 9 8 7 3 8 7 6 4 3 A 6 2 A 6 2 A 9 2 A K 2 45. 46. 47. 48. - - - - Q T 8 6 2 Q T 9 8 3 T 9 8 6 2 Q T 8 3 2 J 9 6 4 2 J 8 7 6 2 J 7 4 3 2 Q 9 8 4 3 A K 9 A 6 2 A K 6 A 6 2 49. 50. 51. 52. - - - - T 8 3 Q T 9 8 6 Q 6 Q T 3 Q J 9 8 7 6 4 Q 9 7 6 3 J 9 8 7 6 4 3 2 T 9 8 7 6 4 3 A 9 2 A 5 2 A K 2 A K 5 53. 54. 55. 56. - - - - 6 3 2 Q T 9 6 3 2 T 9 8 6 3 Q T 6 2 J T 9 7 4 3 2 J 9 6 2 Q T 8 4 2 T 9 8 7 3 2 A K 2 A K 6 A 6 5 A 9 5 57. 58. 59. 60. - - - - Q 6 3 2 T 8 6 2 Q 8 3 T 9 6 2 Q 7 6 4 3 2 J T 8 7 4 2 Q 8 7 6 4 3 2 Q J 9 6 4 2 A 9 2 A 9 2 A K 9 A 6 5 61. 62. 63. 64. - - - - T 9 6 3 Q 9 8 6 9 8 6 2 Q 9 6 3 2 Q 8 6 4 3 2 Q J 6 4 3 2 J T 9 6 3 2 9 7 4 3 2 A K 9 A K 2 A 9 6 A 6 5 65. 66. 67. 68. - - - - 9 8 2 Q 9 8 6 9 6 2 Q 9 8 3 2 T 9 8 7 6 3 2 Q T 9 8 7 2 Q T 7 6 4 3 2 Q T 9 7 2 A 6 5 A 9 6 A K 6 A 9 6 69. 70. 71. 72. - - - - T 9 8 2 Q 8 3 2 Q T 9 8 6 9 6 3 2 J T 8 4 3 2 J 9 7 6 4 2 T 9 8 7 3 Q J 9 6 4 3 A K 2 A 9 2 A 9 6 A 9 6 73. 74. 75. 76. - - - - 9 6 3 2 Q 8 6 2 T 6 2 T 8 6 3 2 Q J T 8 4 3 Q T 8 4 3 2 Q T 8 6 4 3 2 Q 8 7 3 2 A 9 6 A K 2 A K 9 A K 5 77. 78. 79. 80. - - - - Q T 6 3 2 T 9 8 6 T 9 8 6 2 Q T 8 6 3 2 Q J T 9 3 J T 8 7 4 3 8 7 6 4 2 T 7 4 3 A K 9 A 6 5 A K 6 A 9 6 81. 82. 83. 84. - - - - 9 8 3 Q 8 6 2 Q T 9 8 3 Q T 9 8 3 Q J 9 8 7 6 4 T 9 6 4 3 2 Q 8 7 6 3 Q 8 6 4 3 A K 9 A 9 6 A K 2 A 6 2 85. 86. 87. 88. - - - - Q T 6 3 Q 9 Q T 6 Q 8 3 T 9 8 7 3 2 Q T 9 8 7 6 4 3 J 9 8 7 6 3 2 Q J T 9 7 6 3 A 5 2 A 9 2 A K 9 A 6 2 89. 90. 91. 92. - - - - T 6 3 9 3 2 Q T 8 6 3 3 2 Q J T 6 4 3 2 J T 9 7 4 3 2 J 8 6 4 2 J 9 8 7 6 4 3 2 A K 6 A 6 2 A 9 5 A 6 5 93. 94. 95. 96. - - - - T 6 3 Q T 8 6 Q T 9 8 6 Q T 8 6 J T 9 8 7 6 3 J 9 7 6 4 3 Q J 8 7 3 Q J 8 6 3 2 A K 2 A 6 2 A 9 6 A 9 5 97. 98. 99. 100. - - - - Q T 6 3 T 8 6 2 T 9 8 2 Q T 8 3 Q T 9 8 7 4 Q T 9 7 6 4 Q T 8 7 6 3 J T 9 8 7 6 A 6 5 A 6 2 A 5 2 A 9 6 Generated 5471 hands Produced 100 hands As West I would have acted on all of them at this vulnerability, either over (1♠) or over (1♠)-P-(4♠)-P; (P). You may think that's insane, but if these hands are representative and there's a chance that the actual West is anything like me, then the a priori probability of a 0-3 diamond break (~ 0.11) clearly doesn't apply, and I don't think it's even a good approximation unless the field is unrealistically timid or maybe unfamiliar with concepts like 'preempt', 'sacrifice' and (of course) 'Law of Total Tricks'.Only 2 cases are worth simulation, West has a void in ♠West has a singleton ♠KNeither is likely and all other cases result in the same number of tricks. It isn't clear from Tramticket's original post that the opening leader held ♣K. Anyway, Nullve's simulation confirms Stephen Tu's recommendation. Quote Link to comment Share on other sites More sharing options...
PhantomSac Posted December 25, 2018 Report Share Posted December 25, 2018 If you would even consider safety playing on this hand, I would recommend a simple rule, never safety play at MP. That rule is probably wrong once every few years (depending on how much you play), so it won't be too far from wrong, and will prevent you from even thinking about ever making such a serious error as safety playing on this hand! 2 Quote Link to comment Share on other sites More sharing options...
nige1 Posted December 27, 2018 Report Share Posted December 27, 2018 If you would even consider safety playing on this hand, I would recommend a simple rule, never safety play at MP. That rule is probably wrong once every few years (depending on how much you play), so it won't be too far from wrong, and will prevent you from even thinking about ever making such a serious error as safety playing on this hand![hv=pc=n&w=SAKJHA432DA432C32&e=S432H65D765CAKQ54&d=W&v=E&a=1NP3NPPP]200|200|Typical MP pairs problem.You,West, declare 3N.North leads ♠T and South follows with ♠6.Plan the play[/hv] Quote Link to comment Share on other sites More sharing options...
PhantomSac Posted December 27, 2018 Report Share Posted December 27, 2018 [hv=pc=n&w=SAKJHA432DA432C32&e=S432H65D765CAKQ54&d=W&v=E&a=1NP3NPPP]200|200|Typical MP pairs problem.You,West, declare 3N.North leads ♠T and South follows with ♠6.Plan the play[/hv] If you choose to duck a club are you doing it because it makes it more likely that you "make your contract" or are you doing it because it is the percentage play to maximize your tricks? If the former then that is again a horrendous thought process. If you are in 1N or 2N your thought process should be the same on this hand as if you are in 3N. Despite that, I did not say it is never wrong to safety play at MP, I said it is just almost always wrong and anyone who is considering doing it on this hand would be far better served to just never safety play. So if you find a hand where it is right to actually make a safety play in MP as opposed to your actual example, it still does not refute that. FWIW IMO the most common time to safety play in MP is when you are in an extremely good situation that others dont rate to be in (like they have dropped a trick or 2 already that no one would, or you bid a slam with 15 HCP or something). I can't recall making a safety play in a normal contract. For example if your example hand had dummy with AKQxxx of clubs, ducking a club would be normal in imps since while it doesnt maximize your trick expectancy, it maximizes your chance to make your contract, but in MP it would be ridiculous. 1 Quote Link to comment Share on other sites More sharing options...
cherdano Posted December 28, 2018 Report Share Posted December 28, 2018 If you would even consider safety playing on this hand, I would recommend a simple rule, never safety play at MP. That rule is probably wrong once every few years (depending on how much you play), so it won't be too far from wrong, and will prevent you from even thinking about ever making such a serious error as safety playing on this hand!Stronger words have never been spoken about a 2% edge! Quote Link to comment Share on other sites More sharing options...
kuhchung Posted March 4, 2019 Report Share Posted March 4, 2019 omg what on earth did I just read Quote Link to comment Share on other sites More sharing options...
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