Buggy-Samb game 4, 16-8-2001

Buggy - N.Samb 1-1

1.32-28 17-21 2.31-26 19-23 3.28x19 14x23 4.26x17 12x21 5.37-32 7-12 6.41-37 11-17 7.34-29 23x34 8.40x29 20-25 9.32-28 21-26 10.45-40 17-22 11.28x17 12x21 12.46-41 6-11 13.37-32 10-14 14.41-37 11-17 15.33-28 17-22 16.28x17 21x12 17.32-28 14-20 18.39-33 5-10 19.44-39 2-7 20.38-32 16-21 21.36-31 18-22 22.28x17 12-18 23.33-28 21x12 24.39-33 10-14
diagram 1
Contrary to the last two games, Samb has managed to reach a promising position in the middle game. Black's formation is very flexible, and the perspectives for a classical game are quite good.
25.42-38 4-10 26.50-45 20-24 27.29x20 15x24 28.43-39
diagram 2
28... 12-17 is a little pinprick towards Buggy. It prevents the natural 29.31-27, and the combination 29.28-22? 18x36 30.37-31 26x28 31.33x2 fails because of 8-12 32.2x30 25x32. One would expect that 28... 12-17 is soon followed by 18-22. But that doesn't happen. It looks a bit like Samb hesitates to complicate the situation. This will bring him once more into trouble.
12-17 29.48-43 7-11 30.40-34
diagram 3
Suddenly the situation is getting trickier for black. Here Samb spent about 2/3 of his remaining half hour but he doesn't find the right plan. After 1-6 31.49-44 14-19 32.44-40 10-15 33.28-23 18x29 34.34x14 9x20 35.31-27 white gains a significant advantage. Better options for black were 18-22 31.32-27 14-19 32.27x18 13x22, or the centralising 1-7 that was suggested by Buggy. The drawback of 30... 1-6 is that the piece on 6 quickly becomes a passive one.
1-6 31.49-44 14-19 32.44-40 10-15 33.28-23 18x29 34.34x14 9x20 35.31-27
diagram 4
35... 3-9 The right move! It looks like 36.27-21 is very dangerous for black (8-12? 37.32-27! with a big advantage for white), but after 17-22! 37.21-16 11-17 black has nothing to fear.
3-9 36.40-34 17-22 37.27x18 13x22 38.34-30 25x34 39.39x19 9-13 40.45-40 13x24 41.40-34 8-13 42.47-42 11-16 43.43-39 22-27 44.32x21 16x27 45.37-32
diagram 5
45... 27-31? Under pressure of time Samb makes a mistake that could easily have cost him the game. After 20-25 46.32x21 26x17 black wouldn't have had any problems, despite the inactive piece on 15. At first sight this looks dangerous though, so one can imagine that Samb didn't trust it.
27-31 46.42-37 31x42 47.38x47 26-31 48.33-28 13-18
diagram 6
49.39-33? A remarkable moment. With 49.34-30! 24-29 50.39-34 29x40 51.35x44 Buggy could force a winning endgame:
  1. 20-25 52.30-24 6-11 53.44-39 11-17 54.39-33 17-21 55.33-29 31-36 56.28-23 18-22 57.32-28 22x33 58.29x38 15-20 59.24x15 25-30 60.15-10 30-34 61.10-5 34-40 62.23-19 40-44 63.19-14 21-26 64.14-9 W+
  2. 6-11 52.30-25 20-24 53.25-20 11-17 54.20x29 18-22 55.29-23 22x33 56.23-18 17-21 57.18-13 21-27 58.32x21 31-37 59.13-9 33-38 60.44-39 38-42 61.47x38 37-41 62.9-3 W+
These variants both seem quite long. Nevertheless they are not really difficult to find, since the white moves are all very logical, and black has no serious alternatives. Note that the resulting position in variant 2 is extremely complicated for humans. For the computer it's much easier. It 'knows' that the position is winning, since it is stored inside its endgame database. The move that Buggy plays instead may be winning too, but that is not at all sure.
49.39-33 31-36 50.32-27 6-11 51.27-21 11-16 52.28-22 16x27 53.22x13 27-31 54.13-8 31-37 55.8-3 37-41 56.3x25 41-46
diagram 7
57.25-30? For the second time Buggy chooses the wrong one of two promising alternatives. Most likely 57.25-20! would have secured the victory. The best defence for black seems 24-30 (to disturb the white pieces) 58.35x24 46-23 59.33-29 23-5. As was pointed out by Kandaurov during the online analysis, then white can win by constructing the position of diagram 7a.
diagram 7a
White wins, since black cannot stay on the main diagonal: 32-5? 66.29-23 5x46 67.47-41 46x30 68.35x19 W+
57.25-30 24-29 58.33x24 46-23 59.30-25 23x45 60.24-19 45-50
diagram 8
Now it's impossible for white to win. Some variants that illustrate this are: 61.25-14 50-11 and now
  1. 62.19-13 15-20 63.14x25 11-28
  2. 62.35-30 11-33 63.30-25 15-20 64.14-9 20-24 65.19x30 33-28
with in both cases a standard draw position known as 'anti Scouppe'.
61.19-13 50-28
Copyright © 2001, Wieger Wesselink, http://10x10.org.