## The 26-17 Defiance

You may print this and show it to others. But, this article will eventually be part of a book that I am writing. So, please do not distribute it widely.

If you need help reading checkers notation, please print out the numbered board.

I received this message from Ed Gilbert:

I don't think we've met. I'm a checkers programmer and I've written the checkers program called Kingsrow. Brian Hinkle asked me about the Defiance line given on your web site, and after going over it with Kingsrow I think its a black win after 11-15 23-19 9-14 27-23 8-11 22-18 15-22 26-17. I'm forwarding you a copy of my reply to Brian.

Here is Kingsrow's analysis (unless otherwise attributed):

1. 11-15 23-19 2. 9-14 27-23 3. 8-11 22-18 4. 15x22 26x17 5. 6-9(vars. 1,3) (11-15 may also win)30-26(var. 2) 6. 4-8 32-27 (B,C,D) 7. 9-13 24-20 8. 13x22 25x9 9. 5x14 29-25 10. 11-15 27-24 (A) 11. 1-5 25-22 BW, kr search value 206 at 31 ply search.

(A) 25-22 11. 15x24 28x19 12. 8-11 22-18 13. 1-5 18x9 14. 5x14 19-16 BW, kr search value 148 at 31 ply search

(B) 17-13 7. 2-6 24-20 8. 14-18 23x14 9. 9x18 25-22 10. 18x25 29x22 11. 11-15 32-27 12. 15x24 28x19 13. 10-15 19x10 14. 6x15 27-23 BW, kr search value 166 at 31 ply search

(C) 25-22 7. 9-13 22-18 8. 13x22 18x9 9. 5x14 26x17 10. 11-16 24-20 11. 8-11 17-13 BW, kr search value 136 at 29 ply search

(D) 26-22 7. 11-15 17-13 8. 2-6 22-17 9. 8-11 31-26 10. 14-18 23x14 11. 9x18 26-23 BW, kr search value 150 at 31 ply search

Var. 1

If 4-8: 1. 11-15 23-19 2. 9-14 27-23 3. 8-11 22-18 4. 15x22 26x17 5. 4-8 25-22(A,D) 6. 11-15 32-27(C) 7. 6-9*(B) 17-13 14-17 13-6 17-26 31-22 2-9 23-18 8-11 19-16 (27-23 9-13 and 5-9 R. Beckwith) 12-19 22-17 15-22 24-6 1-10 17-13 9-14 should eventually win, Richard Beckwith.

(A) 32-27 6. 6-9 17-13 7. 1-6 25-22 8. 14-17 21x14 9. 10x26 31x22 10. 7-10 23-18 11. 11-16 19-15 12. 10x19 24x15 13. 9-14 18x9 14. 5x14 BW

(B) 7. 8-11 30-26 8. 14-18 23x14 9. 11-16 26-23 10. 15-18 22x15 11. 6-9 15x6 12. 9x18 23x14 13. 16x32 14-10 14. 7x14 17x10 15. 2x9 24-19 16. 9-14 29-25 17. 14-18 21-17 18. 5-9 17-13?(E) 19. 9-14 19-15 20. 18-23 25-21 21. 14-18 15-11 22. 18-22 11-7 23. 23-26 7-2 24. 26-30 BW

(C) 24-20 x 8-11 30-26 (31-26 is no better, R. Beckwith) 11-15 looks like a B.W., R. Beckwith.

(D)

• 30-26 6-9 transposes back to the "6-9 win" (in place of 4-8). R. Beckwith.
• 31-26 6-9 17-13 or 26-22 no better, R. Beckwith.
• 17-13 11-16 24-20 (25-22 14-17) 8-11 25-22 14-17 B.W., R. Beckwith.
• 24-20 6-9 17-13 2-6 is back to the "6-9 win," R Beckwith

(E) May lose. Instead 17-14 9-13 19-15 12-16 15-11 16-19 14-9 13-17 25-21 17-22 9-6 22-25 11-7 25-30 7-2 18-22 2-7 30-25 7-11 22-26 31-22 25-18 6-2 19-23 11-16 32-27 21-17 23-26 17-13 26-30 2-6 18-22 6-9 etc. There is still a lot of play, but Nemesis has red only [+10], so I propose a draw. Richard Beckwith.

Var. 2

If 6-9: 1. 11-15 23-19 2. 9-14 27-23 3. 8-11 22-18 4. 15x22 26x17 5. 6-9 24-20 6. 4-8 32-27 (B) 7. 9-13 27-24 8. 13x22 25x9 9. 5x14 29-25 10. 2-6 30-26 11. 11-15 25-22 12. 6-9 19-16 13. 12x19 23x16 14. 8-11 16-12 15. 9-13 22-17 16. 13x22 26x17 17. 15-18 24-19 18. 18-22 31-27 19. 22-26 27-24 20. 11-15 19-16 21. 14-18 16-11 22. 7x16 20x11 23. 18-23 11-7 24. 23-27 7-2 25. 27-32 24-20 26. 26-31 2-6 27. 31-26 20-16 28. 32-27 16-11 29. 26-22 BW

(B) 17-13 7. 2-6 28-24 8. 11-15 25-22 9. 14-18 23x14 10. 9x25 29x22 11. 15-18 22x15 12. 7-11 BW

Var. 3

If 5-9: 1. 11-15 23-19 2. 9-14 27-23 3. 8-11 22-18 4. 15x22 26x17 5. 5-9 17-13 6. 1-5 24-20 7. 11-15 (C) 31-26 8. 15x24 28x19 9. 4-8 32-27 10. 14-18 23x14 11. 9x18 BW

(C) 7. 3-8 30-26 8. 14-18 23x14 9. 9x18 26-23 10. 18x27 32x23 11. 11-16 {not 11-15, which draws) 20x11 12. 8x24 28x19 13. 7-11 31-27 BW