The beautiful old drawbridge shown above is at the entrance to the walled Dutch town of Heusden, which lies on the Maas River. We think it's a fitting illustration for today's Checker School lesson, which is about the classic "Petterson's Drawbridge" position.

We always ask when we present material on a well-known position: How well do you really know it? We're certain that our more advanced readers know it pretty well, but a thorough review never hurts; and for everyone else, this is a great opportunity to master this very difficult end-game formation. Here are two examples for you to try out. You might wish to attempt the second one first.

R.D. PETTERSON	J. BRADLEY
BLACK	BLACK
WHITE	WHITE
White to Play and Draw	White to Play and Draw
W:W9,20,21,30:B1,3,14,19.	W:WK2,10,20,21:B1,3,K18,K19.

When you've crossed this bridge, or more correctly, these bridges, cross your mouse over to Read More to see the solutions, four sample games, and detailed study notes. If you go over all of this material carefully, you'll be a drawbridge expert (of the checker variety, at least) and your cross-board results will definitely improve.

Solutions

Solutions, lettered notes and commentary are taken from Ben Boland's Famous Positions in the Game of Checkers. Numbered notes are by the Editor with the assistance of the KingsRow computer engine.

Diagram No. 1: 30-25---1, 19-23, 25-22, 23-26, 22-17, 14-18, 17-14, 26-30, 14-10, 30-26, 9-6---A, 26-22, 6-2, 18-23, 2-7*---2, 23-27, 7-2, 27-32, 2-7, 32-27, 7-2, 27-23,, 2-7, 23-19, 7-2, 22-18, now Diagram No. 2.

Diagram No. 2: 2-7---B,3, 1-5, 7-2, 19-15---C, 2-6---D, 5-9, 6-13, 15-6, 20-16, 18-22---E, 16-12, 6-10---F, 13-9---G, 22-18, 21-17---H, 18-22, 17-13*, 22-18, 9-5, 18-15, 5-1, 15-11, 13-9, 11-7, 1-5, 7-2, 5-1, 3-7, 12-8, 7-11, 8-3, 11-15, 3-8, 15-18, 8-11, 18-22, 11-16, 22-25, 16-19, 25-30, 19-23, 2-7, 1-5*, 30-25, 23-26*---4, 25-21, 26-22*, 7-2, 5-1, 10-14, 1-5---5. Drawn.

Game: 11-15, 23-19, 9-14, 22-17, 6-9, 17-13, 2-6, 25-22, 8-11, 27-23, 14-18, 23-14, 9-25, 29-22, 4-8, 26-23, 15-18, 22-15, 11-27, 32-23, 8-11, 31-26, 5-9, 26-22, 9-14, 22-17, 11-15, 24-20, 15-24, 28-19, 10-15, 19-10, 6-15, 17-10, 7-14, 13-9---J, 15-19, 23-16, 12-19. Forms Diagram No. 1. F. W. Drinkwater, Souter Var. 8, Lyman's Problem Book.

Game: 10-14, 22-17, 7-10, 17-13, 3-7, 25-22, 14-17, 21-14, 9-25, 29-22, 11-15, 24-20, 7-11, 23-18, 5-9, 26-23, 1-5, 28-24, 9-14, 18-9, 5-14, 23-18, 14-23, 27-18, 12-16, 31-27, 15-19---K, 24-15, 10-19, 22-17, 19-24, 27-23, 24-27, 18-15, 11-18, 23-14, 27-31, 20-11, 8-15, 14-10, 6-9, 13-6, 2-9, 10-7, 9-13, 17-14, 15-18, 14-9, 4.8, 7-3, 8-12, 3-7, 18-23, 7-11, 31-26, etc. A. J. Heffner, Kear's Encyclopedia, Page 270, Var. 39, 3rd Edition.

Game: 10-14, 24-19, 6-10, 22-17, 9-13, 28-24, 13-22, 25-9, 5-14, 29-25, 11-15, 26-22, 7-11, 23-18, 14-23, 27-18, 11-16, 18-11, 8-15, 31-27, 16-23, 27-11, 3-8, 11-7, 2-11, 22-17, 12-16, 24-20, 16-19, 17-14, 10-17, 21-14, 1-6, 25-22, 19-23, 22-17 11-16, 20-11, 8-15, 14-10, 6-9, 10-7, 9-13, 17-14, 15-18, 14-10, 4-8, 7-3, 8-12, 3-7, 18-22, 10-6, 22-26, etc. H. Moulding lost the Drawbridge Position in this game to T. J. O'Grady, in the Second International Match, 1927.

Game: 12-16, 24-20, 8-12, 28-24, 9-14, 22-17, 3-8, 25-22, 16-19, 24-15, 11-25, 29-22, 8-11, 17-13, 11-16, 20-11, 7-16, 23-19, 16-23, 26-19, 2-7, 27-23, 14-17, 21-14, 10-26, 31-22, 7-11, 22-17, 4-8, 23-18, 11-16, 17-14, 16-23, 14-9, 5-14, 18-2, 8-11, 13-9, 1-5---L, 9-6, 11-16, 2-7, 16-19, 7-11, 19-24, 11-15, 24-27, 15-10, 5-9, 6-2, 9-13, 2-7, 27-31, 7-11, 31-27, etc. J. K. Lyons, Kear's Ency. Page 59, Var. 22, 3rd Edition, also Stiles' Guide, Part 1.

A---This corrects F. W. Drinkwater, who played 21-17 in his No. 546 in Lyman's Problem Book, (winning by 2nd position).

B---2-6, 3-7, 10-3, 1-10, 3-8---I, 10-14, 8-12, 14-17, 21-14, 18-9, 20-16, 9-14, 16-11, 14-10, 11-8, 10-7. Black Wins.

C---18-15, would allow 10-6, to be played.

D---Essential if 10-6, 5-9, 6-1, 3-7, 2-11, 15-8, 20-16, 9-13, 1-5, 18-15, 16-12, 8-11, 5-9, 15-18, 9-5, 18-14. Black Wins by First Position.

E---If 18-14 here, White must force the trunk by repetition; 13-17, 14-18, 17-13, If 18-14, 16-12, 6-10, 13-17, 10-7. Black Wins. Similarly, 6-10, 13-17, 10-6, 17-13; because if 6-10, 13-9, 10-14, 9-13 (9-5 Black Wins by 1st Position), 18-22, 16-12, 22-18, 13-17, 14-10, 17-13, 18-14. Black Wins.

F---22-18, 21-17*, 6-1, 13-9, 18-15, 17-14, 1-5, 9-6, 15-11, 6-10, 5-1, 14-9, 11-7, 10-14,7-2,9-5. Drawn.

G---This may be easier; 21-17, 3-7, 12-8, 7-11, 8-3, 11-15, 3-8, 15-18, 8-11, 18-23, 11-16, 23-26, 16-19, 26-30, 19-23, 22-26 (30-25, 23-26, 22-31, 17-14. Drawn), 17-14. Drawn. H. McKean.

H---9-5, 18-14, 5-1, 14-9, 1-5, 9-6, 21-17, 10-7, 17-13, 6-1, 5-9, 7-10. Black Wins.

I---21-17, 18-15, 3-7, 10-14, 7-10, 15-6, 7-11, 6-9, 11-8, 9-14. Black Wins.

J---Forms No. 546 by Drinkwater, Lyman's Problem Book, 1881.

K---16-19 loses by 18-14, etc.

L---11-16 loses by 2-7, 16-19, 7-11, 19-24, 11-15, 24-27, 15-10, 27-31, 9-6, White Wins. I. Ferrie vs. R. Jordan.

1---As an example of how critical such a position can be, this is the only move to draw. Moves such as 20-16 lose---Ed.

2---Despite this being given as a starred move, 2-6 also draws---Ed.

3---Another example of the need for extremely accurate play---Ed.

4---Black must protect the still-vulnerable man on 6---Ed.

5---Black's only move now is 2-7 as anything else loses a piece. The game might continue 2-7 9-6 702 6-1 14-10 5-9 2-7 etc. Drawn. A very finely balanced ending in which White must play precisely to obtain the draw.

The above position (Diagram No. 1), arose from F. W. Drinkwater's analysis on a "Souter" game between R. Martins and J. Wyllie, 1847. The play ran into Position 546, Lyman's Problem Book, 1881, which had just been published. At a point in the discussion (see above game), Mr. Petterson asked to have the position reset, saying he thought he could draw it, which he did. The players thought so much of it that they called it "Petterson's Drawbridge." It may now be found as No. 1025 in W. J. Wray's Bridge Section of Gould's Problem Book. John Bradley picked up where Petterson left off, his is No. 1026 in Gould's.