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An Immobile Piece May Be Doomed.Return to my Checkers pages
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© Copyright 1997, Jim Loy
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See my article,
An Immobile Piece May Be Doomed.
An elbow is a formation of three immobile pieces forming a right angle, such as White's three pieces surrounded by green, in the diagram. Here, the elbow loses, as it often does. With so many immobile pieces, White runs out of moves: 31-27 4-8 23-18 (otherwise Red will just win with 8-11-15-18) 14-23 27-18 8-11 30-26 10-15 18-14 11-16 20-11 7-16 RW (Red wins a piece with 15-18).
In the diagram, Red probably wants to avoid 1-5, as that would also give him an elbow (at 6, 10, & 14).
The diagrammed position came up as follows: 11-15 23-19 8-11 22-17 3-8 (Whilter) 25-22 9-14 29-25 11-16 26-23 5-9 24-20?? (17-13, meeting the threat of 9-13, should be obvious) 15-24 20-11 8-15 28-19 15-24 27-20 9-13 (This move should be obvious, as well).
Addendum:
Here is another fatal elbow. 11-15 21-17 9-13 (the
Switcher) 25-21 8-11 29-25? Nexus, the program that I use, foolishly makes this
losing move when I turn off its opening book. Red now goes to great lengths to
preserve White's elbow (17, 22, 25): 15-18* (Otherwise 17-14) 23-14 (22-8 loses
right away) 11-15 24-19 15-24 28-19 4-8 27-23 8-11 23-18 6-9 19-15 (Otherwise
11-15 wins right now) 10-19 14-10 (Breaking up the elbow, but at some cost)
7-23 17-14 9-18 22-8 12-16* 8-4 2-7 31-27 5-9 27-18 19-24 (And White will run
out of safe moves) R.W., A. Hynd.