3 pieces behind the diagonal 5-46

Analysis: Wieger Wesselink

In this analysis we will look at some 4 against 2 endgames where white has three pieces behind the main diagonal 5-46. The only way to chase the black king away from this diagonal is to build a suitable capture position. Often this makes the white pieces vulnerable to attacks with the black king.

diagram 1
diagram0.png

Barski 439 , white wins as follows: 1.17-44 16-21 2.44-35 Now black must leave the main diagonal because of 21-26 ? 3.15-10 23x5 4.20-14 5x30 5.35x19 W+. 23-34 3.24-19 ! (and not 3.20-14 21-27 4.24-19 27-32 5.35-24 32-37 6.24-47 34-30 =) 21-27 4.35-24 ! and in this position black is defenseless.

diagram 2
diagram1.png

Barski 440 Draw! White cannot reach the capture position from diagram 1, for example 1.17-8 46-41 2.25-20 41-46 3.35-30 16-21 ! 4. 8x26 46-19 5.30-25 with a standard draw position. Notice that if the white piece on 35 is moved to one of the squares 40/44/45/49/50 the position is still a draw.

diagram 3
diagram2.png

Draw. White has only one plan in this postion: advance with the piece on 47 to 38, and make a capture position. After some quick analysis with the computer it becomes evident that black has many ways to force a draw when white advances the piece on 47. A nice corner case is: 1. 3-12 37-46 2.47-42 46-41 3.42-38 en nu 41-37 * and now white can choose between 1) 4.12-26 37-28 * and 2) 4.12-8 37-26 * 26-37 5. 8-3 with repetitive moves, and 3) 4.38-33 37-26 * 5.12-3 26-31 !! * and now 3.1) 6.20-14 31-9 7.14-10 9-22 8.33-29 16-21 9. 3x26 22-18 etc. = or 3.2) 6.33-28 31-37 * 7.28-22 37-31 8.22-17 31-37 ! and white's position of the king is so awkward that black can simply make a second king after 9.17-12 16-21 10.12-8 21-27 11. 8-2 27-31 with a draw. N.B. also when the white piece on 47 is moved to 48 it is still a draw.

diagram 4
diagram3.png

In this position white can simply win by first advancing with 47 to 24 and then follow the plan in diagram 1.

diagram 5
diagram4.png

In this position black has exactly one way to force a draw: 28-41 * This has everything to do with the variant 2.48-43 16-21 * 3.43-38 41-36 * and because of the black king on the crucial square 36 white cannot advance with 4.15-10 because of the attack 36-47 . If black instead plays the careless move 28-37 ? then white wins after 2.48-43 16-21 3.43-38 37-31 4.15-10 31-4 5.10-5 4-15 6.38-32 ! 15x27 7. 5-32 W+.

diagram 5a
diagram5.png

To increase the understanding of this endgame an extra diagram is useful. Here black has two possible moves, namely 5-23 and 5-41 , both with the objective to prevent the white move 2.42-38 . Suppose white wants to prepare this move with 2.49-43 then black can continue with 41-19 3.42-38 19-23 * (to prevent the move 4.43-49 ) 4.38-33 23-12 ! and white can no longer defend the loose pieces, for example 5.20-14 12-3 * 6.14-10 16-21 7.43x16 3-17 etc. =.

Copyright © 2003, Wieger Wesselink, http://10x10.org.