Return to my Checkers pages
Go to my home page
© Copyright 2003, Jim Loy
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.
This variation is assumed to be a loss: 9-14 23-18 (Double Cross) 14-23 27-18 5-9 (strong, as are several other moves) 21-17?, as 26-23 is usually given a *, meaning it is the only move to draw. So, I studied the 21-17 variation, in an effort to find the win. But I found that wins are few and far between, and (so far) the 21-17 variation may even be easier to defend than the 26-23 variation. Of course 26-23 has been tested for decades, and there is a mountain of analysis in the books. That makes new attacks difficult to find. So, even if 21-17 is easier in a vacuum, it may be more difficult to defend in practice, when a new attack can be invented at will.
Here are my unsuccessful efforts to destroy this variation:
9-14 23-18 14-23 27-18 5-9 21-17 11-15(v.1) 18-11 8-15 17-13 9-14(A) 24-19 15-24 28-19 4-8(B) 26-23 8-11 22-18 14-17 25-21 (32-28 11-16 25-21 16-20 21-14 10-17 30-26 3-8 18-14 8-11 23-18 11-16 26-23 17-22 14-9 20-24 18-15 16-20 draw?) 3-8 21-17 10-17 32-28(C,D) 17-21 31-27(E) 11-16 27-24 7-10 29-25 8-11 25-22 10-15 19-10 6-15 draw.
A -
B - 7-11 26-23 11-15 22-18 15-24 18-9 1-5 (4-8 25-22 8-11 29-25 11-15 22-17 12-16 25-21 draw) 32-28 5-14 28-19 4-8 31-27 8-11 draw.
C - 32-27 11-16 (17-21 29-25 12-16 19-3 11-16 3-10 6-29 23-18 29-25 31-26 draw) 29-25 17-22 25-21 16-20 (1-5 21-17 7-10 18-15 5-9 15-11 8-24 27-11 9-14 30-26 14-21 26-17 21-25 draw) 21-17 7-10 18-14 10-15 19-10 6-15 13-9 1-5 17-13 8-11 14-10 5-14 13-9 11-16 10-6 draw.
D - 30-26 (18-14 11-16 29-25 8-11 31-26 16-20 19-16 12-19 23-16 6-9 13-6 2-18 16-12 7-10 draw) 17-21 32-28 11-16 28-24 7-10 18-15 16-20 23-18 20-27 31-24 12-16 19-3 16-28 26-23 draw.
E - 29-25 (28-24 7-10 30-26 draw) 12-16 19-3 11-16 3-10 6-29 23-18 2-7 18-15 16-19 31-27 1-6 27-23 19-26 30-23 29-25 23-18 draw.
Var. 1 - 9-13 (12-16 17-14 10-17 22-13 16-20 24-19 11-15 draw) 25-21 11-15 12-16 (11-15 18-11 8-15 17-14 10-17 21-14 4-8 29-25 draw? or 14-9 PP may draw) 17-14 10-17 21-14 6-10 29-25 10-17 25-21 16-20 21-14 20-27 31-24(A) 11-15 18-11 8-15 24-19 15-24 28-19 4-8 32-27(B) 8-12(C) 27-24 3-8 24-20 8-11 (1-6 14-9 6-10 22-18 8-11 9-5 11-15 18-11 7-23 26-19 2-7 5-1 7-11 1-6 11-15 30-25 15-24 6-15 draw) 22-18 1-6 30-25 13-17 25-21 17-22 21-17 22-26 24-20 26-31 19-16 draw.
A - 32-23 11-15 (8-12 or 11-16 draw?) 18-11 8-15 (7-16 14-9 8-11 draw) 23-19 15-24 28-19 4-8 26-23 8-11 23-18 7-10 14-7 3-10 30-26 1-6 22-17 13-22 26-17 draw.
B - 26-23 8-11 (7-11 draw) 32-27 7-10 14-7 3-10 22-18 13-17 18-15 11-18 23-7 2-11 draw.
C - 7-10 (1-5 27-23 7-10 14-7 3-10 23-18 10-14 18-9 5-14 30-25 2-6 25-21 8-11 26-23 6-9 22-18 13-17 draw) 14-7 3-10 26-23 8-11 27-24 2-7 22-18 13-17 24-20 17-22 19-16 22-26 16-12 1-5 12-8 10-15 8-3 15-22 3-10 draw.