January 27, 2008
"THE THEORY OF THE MOVE"
Taken from "The British Draughts Player" by Various Authors
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Note: Red/Black is used interchangeably to identify pieces To have the move signifies the occupying of that position on the board which will eventually cause the player who has it to have the last play, as in this position-B. man on 2, W. man on 31. B. to play, he moves 2-7, 31-26, 7-10, 26-23, 10-15, and W. cannot move. The number of pieces in Red's system is odd. The easiest way to find if you have the Move is by Martins' method, which is as follows:-If you are playing Blacks, consider 1,2,3, and 4 as the bottom squares of your system--1, 9, 17, 25; 2, 10, 18, 24; 8, 11, 19, 27: and 4, 12-20-28, forming the system. Count all the pieces on this system, and if odd, and your turn to play, you have the Move. |
Red to Play and Win Scan down for enlarged numbered board
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End Position 10-15 blocks White sc
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If you are playing Whites, reckon your own system--29, 21, 13, 5: 30, 22, 14, 6: 31, 28, 15, 7and 32, 24, 16, 8. See how many pieces are on these squares, and if the number be odd, and your turn to play, you have the Move; but if even, and your turn to play, your opponent has the Move.
In diagram No. 1, you play Black and have the Move, because the systems contain an odd number of pieces: the White system contains one piece; the Red system contains 3 pieces. Or another way, Black to move - count the total in Black's system (1,2,3,4) totals 3 pieces an odd number so Black has the move, and by moving 15-19, blocks both white pieces.
The advantage of the Move may be gained by the player who has not the Move forcing one of his opponent's men into a double corner, as in playing a similar position to No. 2. According to the theory B. has not the Move, but my playing 11-15, 4-8-15-18, 8-11, 18-14 (forcing the man on 9 into 5), 14-18, B. has gained the Move, and wins. It will be seen that in this and similar positions-to have the Move is a disadvantage.
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Diagram 1 - Black to Play
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Diagram 2 Black to Play
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The Move can usually be altered by "manning,"--that is to say by giving one piece and taking another in exchange; although an exchange does not in every instance alter the move, as the following will draw: B. man on 15, king on 26; W. man on 22, king on 10. W. to play; he has not the Move. He takes 10-19, B. takes 26-17. This exchange does not alter the Move, because the piece on 10 is in the same system as the capturing piece on 26 . |
White to Play 10-19, 26-17 - Exchange does not alter the move
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In the below diagram you play Black and have the Move, because the system contains an odd number of pieces; the W. system contains one piece; the B. system contains three pieces.
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In the below diagram the position is a draw--B. Kings 11, 25; W. Kings 10, 18; but if White plays 10-15 Red would play 25-22 and win, because neither of the capturing pieces are removed from the board.
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Other examples of exchanges might be given, but too many are apt to cause confusion; it is therefore safest and advisable, in some critical situations, to dispense with theory and depend upon practical calculation to decide whether an exchange of pieces will gain or lose the Move.
To calculate the Move with an unequal number of men properly much depends upon the ability of the player. In certain positions he may be able to hold one of his adversary's men, or force one to the side of the board. To decide upon which side the men must be held or forced will be found a most important factor, as it is imperative that it shall be held on the proper side. Mr. Pattterson's rule to decide this is the best. He says if the number of pieces is odd the Move is on your double-corner side; if even it is on the single-corner side of the board. He gives Payne's and Tregaskis's positions as illustrations, and also one by Mr. J.K. Lyons.
In the first place apply the rule to Payne's position - B. man 13, kings 14, 15. White Kings 22, 26. White to move. Count the pieces in White's system, 13, 14, 15, 25 equals 4, the result is even, therefore the man must be held on the single-corner side. If it were Red to move, White would lose. However, as White has to play, he forces the draw thus: 26-23, 14-17, 23-26, 15-10, 22-25, 17-21, 25-22, 10-14, 26-30, 14-17, 22-18. Drawn.
Now apply the rule to Tregaskis's position---Red men 5, 6, 12. White man 8, king 19 as in below Diagrams
- we count in White's system, 5, 6, 8 equals 3; the result being odd, we select the double corner side to hold the man; and play thus:-- 8-3 6-10 3-7 10-14 7-10 14-18 10-15 18-22 19-23 22-25 15-18 25-30 18-22 12-16 23-27 5-9 22-18 30-25 18-15 25-22 15-11 16-20 11-15 9-14 15-19 14-17 19-23 17-21 27-31 22-17 31-27 21-25 27-31 25-30 31-27 17-14 27-31 30-25 31-27 25-22 27-32 22-18 23-19 18-22 19-23 14-10 32-27 10-7 27-31 7-11 23-19 22-17 31-27 17-14 27-23 14-10 23-18 10-7 18-23 7-3 23-27 3-8 27-23 8-12 23-27 11-16 27-23 Drawn.
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Tregaskis's position---Red men 5, 6, 12. White man 8, king 19
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Final Position of Tregaskis's Rule 27-23 - Drawn.
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For further illustration take Mr. Lyon's instructive position--Red men 9, 11, king 2: White kings 10, 26. If White to move--in White's system 0 even; so now White forces Red man to 13 and holds him there, because the rule indicates the single-corner side for the Move. Play thus: 26-22, 11-16, 22-18, 16-19, 10-14, 9-13, 18-22, 19-23, 14-18, 23-27, 22-25, 27-31, 18-22, 2-6, 25-21. Drawn, as in Payne's position. With Red to move the pieces in his system are 5, odd, therefore force the piece on square 11 to the double-corner side, and draw thus:--11-16, 26-23, 9-13, 10-15, 13-17, 15-19, 16-20, 23-18, and draw by similar lines of play to that of Mr. Tregaskis. See below Diagrams.
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Lyon's Position White to Move End Position-Drawn
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Lyon's Position Red to Move End Position-Drawn
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