Bear off cube action

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Lecture in Merit Open 2013 (Cyprus).
Video can be found here. http://www.youtube.com/watch?v=9sv5opV2r_Y
I talked about two main theme.
1, Nroll vs Nroll
2, Two men bear off

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  • Indeed it does. But compare slide 13 with slide 12 (the problem).
    Those are different positions.
    When you examine slide 13, you will notice the position op slide 12 is hidden.
    Actually there are 3 positions piled up in slide 13.
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  • It shows the situation that White rolls 21,21 (twice in a row) and Red has redouble. It is a part of the reason why the original position was a take for Red.
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  • Slide 13...
    The correct board is hidden (there are three boards piled up)
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Bear off cube action

  1. 1. Bear off cube action by mochy @ Merit Backgammon Open 2013
  2. 2. Today’s agenda 1) N roll vs N roll 2) Two men bear off
  3. 3. Why Important? Each decision in the bear off is CRITICAL as Equity difference is usually very large. Cube gets high in the end game much more often. It shows the nature of the game. You can’t win without taking a risk.
  4. 4. True N roll vs N roll 1) All checkers are piled on the low points. 2) You never miss. 3) All doublets should work.
  5. 5. Problem 1 White on roll. Cube action? 1) No double & Take 2) Double & Take 3) Double & Pass
  6. 6. Problem 1 answer 3) Double & Pass Red has only 21%. Much lower than 25%.
  7. 7. Correct Cube Action 2 roll vs 2 roll = Double / Pass 14% 3 roll vs 3 roll = Double / Pass 21% 4 roll vs 4 roll = (Re)Double / Take 25.5% 5 roll vs 5 roll = Double / Take 28% (No redouble)
  8. 8. Problem 2 White on roll. Cube action? 1) No double & Take 2) Double & Take 3) Double & Pass
  9. 9. Problem 2 answer 2) Double & Take White loses with 21. (Red redoubles and white must pass) 5.5% + 21% > 25%
  10. 10. Problem 3 White on roll. Cube action? 1) No double & Take 2) Double & Take 3) Double & Pass
  11. 11. Problem 3 answer 2) Double & Take 32, 31, 21 are misses. 6/36 = 17% 17% + 14% > 25%
  12. 12. Problem 4 White on roll. Cube action? 1) No double & Take 2) Double & Take 3) Double & Pass
  13. 13. Problem 4 answer 2) Double & Take 1) 11, 22 don’t work. 2)Rolling an ace three times! 3)21, 21 makes red redouble!
  14. 14. Problem 5 White on roll. Cube action? 1) No double & Take 2) Double & Take 3) Double & Pass
  15. 15. Problem 5 answer 3) Double & Pass Both sides have non working doublets. (11, 22, 33) It hurts Red much more ! Red needs to roll doubles, White doesn’t.
  16. 16. Two men bear off
  17. 17. Problem 6 White to play 21. 1) 6/3 2) 5/2 3) 6/4 5/4
  18. 18. Problem 6 answer 1) 6/3 5&3 14 numbers 6&2 13 numbers 4&4 11 numbers
  19. 19. The rule 1 ) If you can bear off, do so. 2) Never put checkers on the same point 3) Magic Number “31524” It is the ranking of the gap between two checkers. 3 pips apart is the best, 1 pip apart is the second… and so on.
  20. 20. Problem 7 1) 6/2 2) 5/1 3) 6/3 5/4
  21. 21. Problem 7 answer 1) 6/2 5 & 2 – 19 numbers (3 pips apart) 4 & 3 – 17 numbers (1 pip apart) 6 & 1 – 15 numbers (5 pips apart)
  22. 22. Problem 8-1 White on roll. Cube action? 1) No double & Take 2) Double & Take 3) Double & Pass
  23. 23. Counting 1) Count the lesser! 2) Count them in order. (from big to small or vice versa) 3) Count non-doublet first, multiply by 2, then go for doublet. - 65, 64, 63, 62, 61, 54,,,,21. (multiply by 2) - 66, 55, 44, 33, 22, 11
  24. 24. Problem 8-1 answer 2) Double & Take 19 numbers are little more than 18. You are a tiny favorite.
  25. 25. Flip a coin?
  26. 26. Problem 8-2 White on roll. Cube action? 1) No double & Take 2) Double & Take 3) Double & Pass
  27. 27. Problem 8-2 answer 2) Double & Take White would miss with any 1 except 11. (10 numbers) 10 numbers is more than 9. (9/36 = 25%)
  28. 28. 2 & 2 is a STRONG double
  29. 29. Problem 9 White on roll. Cube action? 1) No redouble & Take 2) Redouble & Take 3) Redouble & Pass
  30. 30. Problem 9 answer 1) No Redouble & Take White is only a tiny favorite (flip a coin!) Don’t give red a chance to offer a very strong redouble! Also known as “Jacoby Paradox”
  31. 31. Problem 10 White on roll. Cube action? 1) No double & Take 2) Double & Take 3) Double & Pass
  32. 32. Problem 10 answer 3) Double & Pass To take, your position needs to be better than your opponent. Or you must have an instant redouble if he misses.

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