An Introduction to Advanced Doubling

1. An Introduction to Advanced Doubling Chris Bray November 2011

2. Introduction Basics Revisited Lessons & Concepts from the Bots Two Examples Using Assets No Anchor Broken Primes Back Games Complexity Summary Agenda

3. Introduction

4. “There’s more to learn, but my problem is more about execution than learning. It’s dangerous if you can’t play very well, but it’s a lot worse if you don’t know you can’t play very well. ” Malcolm Davis (2011)

5. “If two absolutely perfect players engaged in a match, there would never be an accepted double.” Georges Mabardi Backgammon to Win (1930)

6. “Good checker play will never compensate for serious errors of judgement in doubling.” Paul Magriel – Backgammon (1976)

7. “Given the same amount of intelligence, timidity will do a thousand times more damage than audacity”- Karl von Clausewitz

8. “I will often redouble what I am pretty sure is not a redouble on the chance that my opponent will pass. This is big key to winning matches about which the bots are clueless.” Nack Ballard (2004)

9. Basics Revisited (The Known Universe)

10. The Five Possibilities Not good enough to double Take 1. Double/Redouble Double/No Redouble Take Take 3. 2. Double/Redouble Pass 4. Too good to double Pass 5. Player 1 Player 2

11. Woolsey’s Law of Doubling • If I were doubled in my opponent’s position • is it a take? • Yes, I’m absolutely sure it is a take • No, I’m absolutely sure it is a pass • I’m not 100% sure If the answer is (c) then it is ALWAYS correct to double.

12. Simple Holding Game Correct Action: Double/take

13. Pip Counts & Doubling • Absolute Minimum: • Use a 10% guideline • Intermediate Level: • Apply the 8-9-12 Rule • Expert Level • Use the Ward Formula with Trice’s Rule 62 • Rudimentary knowledge of match equities • World Class Level • Understand & use Effective Pip Counts • Learn the rest of Trice’s formulae • Full understanding and application of match equity charts and formulae

14. PRaT (1) If you are ahead/better in two of the three main elements you should at least be considering doubling. • Position • Who has the better static elements such as: • Number of home board points? • Prime or potential prime? • Connectivity? • Anchor in the opponent’s board? • Race • Who leads in the pip count? • Threat • Are you threatening to improve your position by: • Making new points? • Hitting your opponent’s blot(s)? • Bringing your last man home safely?

15. PRaT (2) • Opponent • Human beings are different! • Three broad types: • Conservative • ‘Normal’ • Steamer • Match • In a match the score is critical • Learn the cube actions for common scores • Test your opponent early

16. Stack and Straggler Correct Action: Double/huge drop

17. Containment Benchmark Correct Action: Double/drop (just)

18. Lessons & Concepts from the Bots

19. Key Factors • Anchors are undervalued when considering a take, conversely lack of an anchor is sometimes ignored with disastrous consequences • An irreparably damaged home board often leads to a double being dropped • Dead checkers are ruinous • Long-term assets (e.g. primes) can be very powerful • A broken prime is still very strong • A well-timed back game can be lethal • Command of space is more important than you think Warning: These elements are not mutually exclusive

20. A Simple (?) Example

21. Game Position 1 Correct Action: No Double (just)/Take

22. Game Position 2 Correct Action: Double/Take

23. Game Position 3 Correct Play: 20/15, 20/18

24. Game Position 4 Correct Action: Double/Huge Drop

25. Second Example

26. Position A Correct Action: Redouble/Borderline Take

27. Position B Correct Action: Redouble/Drop

28. Position C Correct Action: Redouble/Big Drop

29. Using Assets

30. Very Early Double? Correct Action: Monster double/skinny take!

31. Space and Asset Correct Action: Strong double/take

32. Good enough? Correct Action: Double/Big drop

33. Too early? Correct Action: Big double/take

34. World Championship 2011 Correct Action: Double/Drop (just)

35. No Anchor

36. Single Checker Correct Action: Double/Drop (just)

37. Double Checker Correct Action: Double (just)/Easy take

38. Broken Primes

39. Broken Prime 1 Correct Action: Double/Take

40. Broken Prime 2 Correct Action: Double/Take

41. Back Games

42. Back Game 1 Correct Action: Double/Huge Drop

43. Back Game 2 Correct Action: Double (just)/Trivial Take

44. Complexity

45. In the Balance Correct Action: Redouble/Comfortable Take

46. Many Factors Correct Action: Double/Take

47. Summary

48. Key Factors • Anchors are undervalued when considering a take, conversely lack of an anchor is sometimes ignored with disastrous consequences • An irreparably damaged home board often leads to a double being dropped • Dead checkers are ruinous • Long-term assets (e.g. primes) can be very powerful • A broken prime is still very strong • A well-timed back game can be lethal • Command of space is more important than you think Warning: These elements are not mutually exclusive

49. Next Steps • Make sure you know the basics • Analyse your own games using XG • Use structured study • Remember Clausewitz Doubling really is very difficult!!

50. “Lack of skill, discipline or fitness are common amongst all but the top sportspeople. Once you get to the top it’s pressure, the influence of the opposition or mental toughness.” Matthew Pinsent