perpetual check (or not!)

[Frank Schneider]

Geschrieben von: / Posted by: Frank Schneider at 19 March 2000 09:24:53:
Hi all,
here are two testpositions, one where there is a perpetual check (1. Rg5+) and
one, slighlty modified, where the perpetual check is no longer possible.
Which program sees a draw in the first position but not in the 2nd?
Frank

Pos 1:
[D]r7/8/4p3/5b1k/3p3r/Np6/1P4R1/K5R1 w - -
Rg5+ draws by perpetual check (or stalemate)
Pos 2:
[D]r7/8/8/4p2k/3pb2r/Np6/1P4R1/K5R1 w - -
now there is no longer a perpetual check after Rg5+, e.g.:
1. Rg5+ Kh6 2. Rh5+ Kxh5 3. Rg5+ Kh6 4. Rh5+ Kg7 5. Rg5+ Kf7 6. Rg7+ Ke8 7.
Re7+ Kd8 8. Rd7+ Kc8 9. Rc7+ Kb8 10. Rc8+ Ka7 11. Rc7+ Bb7



GromitChess Home Page

[Volker Pittlik]

Geschrieben von: / Posted by: Volker Pittlik at 19 March 2000 12:12:58:
Als Antwort auf: / As an answer to: perpetual check (or not!) geschrieben von: / posted by: Frank Schneider at 19 March 2000 09:24:53:
Crafty 17.10SMP agrees:
Position 1

12 8.99 -4.37 1. Rd2 d3 2. Kb1 Rc8 3. Rf1 Kg5 4.
Rg2+ Rg4 5. Rd2 Rf4 6. Rh1 Be4 7. Rc1
12 9.19 ++ 1. Rg5+!!
12 9.21 0.00 1. Rg5+ Kh6 2. Rh5+ Kxh5 3. Rg5+ Kxg5
-------------------------------------------------------------------------
Position 2

...
15-> 2:04 -3.55 1. Rg5+ Kh6 2. Rxe5 d3 3. Re6+ Kh7
4. Rd6 Rh2 5. Re6 Re2 6. Re7+ Kh8 7.
Re6 d2 8. Rh6+ Bh7 9. Rd1 Rc8 10. Rhh1
Kg7 11. Rhg1+ Bg6 12. Nb5
-------------------------------------------------------------------------
LGv2.5 disagrees (Position 2):
Position 1

8 -444 423 1998100 g2e2
8 -445 456 2113620 g2e2 d4d3 e2e5 h4d4 g1d1 d3d2 e5e2
9 -467 534 2515944 g2e2 d4d3 e2e5 h4d4 g1d1 h5g6 e5e3 g6f6
I: .
9 0 619 2936226 g2g5
9 0 623 2960402 g2g5 h5h6 g5h5 h4h5 g1g6 h6h7 g6g7 h7h8 g7h7 h8g8 h7g7 g8f8 g7f7 f8e8 f7e7 e8d8 e7d7 d8d7
10 0 633 3061924 g2g5 h5h6 g5h5 h4h5 g1g6 h6h7 g6g7 h7h8 g7h7 h8g8 h7g7 g8f8 g7f7 f8e8 f7e7 e8d8 e7d7 d8d7
-------------------------------------------------------------------------
Position 2

6 -284 14 61454 g2g5 h5h6 g5e5 a8a6 e5b5 e4c2 b5e5
7 -282 34 161220 g2g5 h5h6 g5e5 a8a6 g1d1 e4c2 d1g1 h4f4 g1g3
8 -272 158 771286 g2g5 h5h6 g5e5 h4f4 e5e6 h6h5 e6e5 h5h4 g1d1 a8a4
I: .
9 0 1248 6609766 g2g5 h5h6 g5e5 h4f4 e5e6 h6h5 e6e5 h5h4 g1d1 a8a4
9 0 1263 6787664 g2g5 h5h6 g5h5 h4h5 g1g6 h6h7 g6g7 h7h8 g7h7 h8g8 h7g7 g8f8 g7g8 f8f7 g8g7 f7f6 g7g6 e4g6
10 0 1277 6911470 g2g5 h5h6 g5h5 h4h5 g1g6 h6h7 g6g7 h7h8 g7h7 h8g8 h7g7 g8f8 g7g8 f8f7 g8g7 f7f6 g7g6 e4g6
11 0 1302 7117060 g2g5 h5h6 g5h5 h4h5 g1g6 h6h7 g6g7 h7h8 g7h7 h8g8 h7g7 g8f8 g7g8 f8f7 g8g7 f7f6 g7g6 e4g6
12 0 1347 7518788 g2g5 h5h6 g5h5 h4h5 g1g6 h6h7 g6g7 h7h8 g7h7 h8g8 h7g7 g8f8 g7g8 f8f7 g8g7 f7f6 g7g6 e4g6
I: .
13 0 1438 8153308 g2g5 h5h6 g5h5 h4h5 g1g6 h6h7 g6g7 h7h8 g7h7 h8g8 h7g7 g8f8 g7g8 f8f7 g8g7 f7f6 g7g6 e4g6
I: .
14 0 1623 9312808 g2g5 h5h6 g5h5 h4h5 g1g6 h6h7 g6g7 h7h8 g7h7 h8g8 h7g7 g8f8 g7g8 f8f7 g8g7 f7f6 g7g6 e4g6
I: .
15 0 2064 12065914 g2g5 h5h6 g5h5 h4h5 g1g6 h6h7 g6g7 h7h8 g7h7 h8g8 h7g7 g8f8 g7g8 f8f7 g8g7 f7f6 g7g6 e4g6
I: .
16 0 3238 18837070 g2g5 h5h6 g5h5 h4h5 g1g6 h6h7 g6g7 h7h8 g7h7 h8g8 h7g7 g8f8 g7g8 f8f7 g8g7 f7f6 g7g6 e4g6
I: .
17 0 6281 35604348 g2g5 h5h6 g5h5 h4h5 g1g6 h6h7 g6g7 h7h8 g7h7 h8g8 h7g7 g8f8 g7g8 f8f7 g8g7 f7f6 g7g6 e4g6
I: .
18 0 13394 75498842 g2g5 h5h6 g5h5 h4h5 g1g6 h6h7 g6g7 h7h8 g7h7 h8g8 h7g7 g8f8 g7g8 f8f7 g8g7 f7f6 g7g6 e4g6
-------------------------------------------------------------------------
SOS_991103 finds Rg5+ but does not see the draw:
Position 1

9 -411 270 325133 Rd2 d3 Kb1 Rg4 Rd1 e5 Rxd3 Bxd3+ Rxd3 (120 knps)
10 -414 893 1017998 Rd2 Ra4 Rg2 d3 Rg5+ Kh6 Rg8 Rg4 Rxg4 Rxg4 Rxg4 Bxg4 Nc4 Kg5 (114 knps)
11 -422 2010 2383179 Rg5+ Kh6 Rg2 Rh5 Rd2 e5 Rc1 Kg6 Rg2+ Kf7 Rc2 (119 knps)
12 -422 2189 2609115 Rg5+ Kh6 Rg2 Rh5 Rd2 e5 Rf1 d3 Kb1 e4 Nc4 Bh3 Rf7 (119 knps)
12 -418 2304 2745798 Rg5+ Kh6 Rh5+ Kxh5 Rg5+ Kh6 Rg6+ Kh7 Rg7+ Kh8 Rh7+ (119 knps)
13 -421 6021 7022729 Rg5+ Kh6 Rg2 d3 Rd2 e5 Kb1 Rg8 Re1 Kg5 Nb5 Rh8 Rg2+ (117 knps)
14 -422 9940 11409988 Rg5+ Kh6 Rg2 d3 Rd2 Kh5 Kb1 Rc8 Rf1 Rg4 Nb5 (115 knps)
-------------------------------------------------------------------------
Position 2
0 -351 0 0
1 -353 0 30 Rg5+ Kh6
2 -371 0 448 Rg5+ Kh6 Rg8 Rxg8 Rxg8
3 -371 0 485 Rg5+ Kh6 Rg8 Rxg8 Rxg8
4 -371 0 1073 Rg5+ Kh6 Rg8 Rxg8 Rxg8
5 -401 10 18356 Rg5+ Kh6 Rg8 Rxg8 Rxg8 d3 (168 knps)
6 -410 29 42852 Rd2 d3 Kb1 e5 Rf2 Be4 (144 knps)
7 -411 54 71825 Rd2 d3 Kb1 Rg4 Rd1 e5 Rxd3 Bxd3+ Rxd3 (131 knps)
8 -419 134 179234 Rd2 d3 Kb1 e5 Nb5 Rg8 Re1 e4 (133 knps)
9 -419 154 203606 Rd2 d3 Kb1 e5 Nb5 Kh6 Rf2 (132 knps)
9 -411 270 325133 Rd2 d3 Kb1 Rg4 Rd1 e5 Rxd3 Bxd3+ Rxd3 (120 knps)
10 -414 893 1017998 Rd2 Ra4 Rg2 d3 Rg5+ Kh6 Rg8 Rg4 Rxg4 Rxg4 Rxg4 Bxg4 Nc4 Kg5 (114 knps)
11 -422 2010 2383179 Rg5+ Kh6 Rg2 Rh5 Rd2 e5 Rc1 Kg6 Rg2+ Kf7 Rc2 (119 knps)
12 -422 2189 2609115 Rg5+ Kh6 Rg2 Rh5 Rd2 e5 Rf1 d3 Kb1 e4 Nc4 Bh3 Rf7 (119 knps)
12 -418 2304 2745798 Rg5+ Kh6 Rh5+ Kxh5 Rg5+ Kh6 Rg6+ Kh7 Rg7+ Kh8 Rh7+ (119 knps)
13 -421 6021 7022729 Rg5+ Kh6 Rg2 d3 Rd2 e5 Kb1 Rg8 Re1 Kg5 Nb5 Rh8 Rg2+ (117 knps)
14 -422 9940 11409988 Rg5+ Kh6 Rg2 d3 Rd2 Kh5 Kb1 Rc8 Rf1 Rg4 Nb5 (115 knps)
-------------------------------------------------------------------------
Exchess3.11 disagrees (Position 1):
Position 1

Starting search on position:
r7/8/4p3/5b1k/3p3r/Np6/1P4R1/K5R1 w - -
Target search time: 36000000
Starting depth: 1
Game stage: 3
1. -3.87 0 31 1. Rg5+
2. -4.36 0 315 1. Rg5+ Kh6
3. -4.36 0 877 1. Rg5+ Kh6 2. Rg5g3
4. -4.45 0 3780 1. Rg5+ Kh6 2. Rg1g2 Rh1+
5. -4.41 0 8109 1. Rg5+ Kh6 2. Rh5+ Rxh5 3. Rg6+
6. -4.41 0 15893 1. Rg5+ Kh6 2. Rh5+ Rxh5 3. Rg6+ Kh7
7. -4.41 0 18859 1. Rg5+ Kh6 2. Rh5+ Rxh5 3. Rg6+ Kh7 4. Rg7+
8. -4.41 0 24804 1. Rg5+ Kh6 2. Rh5+ Rxh5 3. Rg6+ Kh7 4. Rg7+ Kh8
9. -4.41 0 29929 1. Rg5+ Kh6 2. Rh5+ Rxh5 3. Rg6+ Kh7 4. Rg7+ Kh8 5. Rh7+
10. ++ 0 72231 1. Rg5+
10. -4.12 0 102963 1. Rg5+ Kh6 2. Rh5+ Rxh5 3. Rg6+ Kh7 4. Rg7+ Kh8 5. Rh7+ Kg8
11. -4.12 1 207032 1. Rg5+ Kh6 2. Rh5+ Rxh5 3. Rg6+ Kh7 4. Rg7+ Kh8 5. Rh7+ Kg8 6. Rg7+
12. --
12. -4.61 16 2445025 1. Rg5+ Kh6 2. Rh5+ Rxh5 3. Rg6+ Kh7 4. Rg7+ Kh8 5. Rh7+ Kg8 6. Rh8+ Kf7
13. --
13. -5.10 158 22866077 1. Rg5+ Kh6 2. Rh5+ Rxh5 3. Rg6+ Kh7 4. Rg7+ Kh8 5. Rh7+ Kg8 6. Rh8+ Kf7 7. Rh7+
13. -4.99 300 43456840 1. Rc1 d3 2. Rd2 e5 3. Kb1 Rc8 4. Rf2 Bg6 5. Rd2 Rxc1+ 6. Kxc1 e4 7. Nc4
14. -5.12 536 77960542 1. Rc1 Rg4 2. Rxg4 Bxg4 3. Kb1 Bf5+ 4. Ka1 d3 5. Rd1 e5 6. Rh1+ Kg5 7. Rg1+ Bg4
node_count = 127852742 quiescent nodes = 13558945 eval_count = 73319941
hash hits = 16202385 hash moves = 1031339 pawn hash hits = 72182955
node_rate = 47041 null cuts = 12893612 exten = 8365609 int_iter = 31
egtb_probes = 2378 egtb_hits = 2378
Return move from search: Rc1
-------------------------------------------------------------------------
Postion 2

Starting search on position:
r7/8/8/4p2k/3pb2r/Np6/1P4R1/K5R1 w - -
Target search time: 36000000
Starting depth: 1
Game stage: 3
1. -2.59 0 30 1. Rg5+
2. -3.09 0 385 1. Rg5+ Kh6
3. -3.09 0 781 1. Rg5+ Kh6 2. Rxe5
4. -3.04 0 2322 1. Rg5+ Kh6 2. Rxe5 d3
5. -3.04 0 4924 1. Rg5+ Kh6 2. Rxe5 d3 3. Re6+
6. ++ 0 12603 1. Rg5+
6. -2.49 0 31913 1. Rg5+ Kh6 2. Rxe5 d3 3. Rb5 d2
7. -2.54 0 65153 1. Rg5+ Kh6 2. Rxe5 d3 3. Rb5 d2 4. Rb6+
8. -2.64 2 405541 1. Rg5+ Kh6 2. Rxe5 Rg8 3. Rf1 d3 4. Rb5 d2
9. -2.68 4 671951 1. Rg5+ Kh6 2. Rxe5 Rg8 3. Re1 Bg6 4. Rb5 Bf7 5. Rf5
10. -2.92 7 1149052 1. Rg5+ Kh6 2. Rxe5 Rg8 3. Re1 Bc2 4. Re7 d3 5. Re1e6+ Kg5
11. -2.99 38 5384725 1. Rg5+ Kh6 2. Rxe5 d3 3. Re6+ Kh7 4. Re7+ Kh8 5. Rd7 Rh7 6. Rd6
12. -3.00 61 8842426 1. Rg5+ Kh6 2. Rxe5 d3 3. Re6+ Kh7 4. Re7+ Kh8 5. Rd7 Rf8 6. Rd1 Rhf4
13. -3.10 124 17972345 1. Rg5+ Kh6 2. Rxe5 d3 3. Re6+ Kh7 4. Rd6 Rh2 5. Rd4 Re2 6. Rd1 Re3 7. Kb1
node_count = 18883618 quiescent nodes = 1901151 eval_count = 10583474
hash hits = 2739766 hash moves = 270647 pawn hash hits = 10309490
node_rate = 144425 null cuts = 1801041 exten = 1153875 int_iter = 19
egtb_probes = 828 egtb_hits = 828
Return move from search: Rg5+
-------------------------------------------------------------------------
Volker