True Legend

[Paloma]

Yes, that's the win and it's forced mate. 25..fg 26. Ng5! and after tossing pieces Black is mated.

Many programs miss the mate let alone Game 3-0.

White to play and mate in 10.

I don't belive it's a mate, eg. 26...Qbb2! 27.Bxb2 Qxb2+ 28.Kg3 Qf2+! 29.Kxf2 Rxf6+ 30.exf6 Bxf6 31.Qd5+ Kh8
No mate in sight!

[AdminX]

[d]1r3rk1/3bbppp/1qn2P2/p2pP1P1/3P4/2PB1N2/6K1/qNBQ1R2 w - - 0 1

Analysis by Houdini 1.5a x64:

1.Bxh7+ Kxh7 2.Rh1+ Kg8 3.Rh8+ Kxh8 4.Qh1+ Kg8 5.g6 Qbb2+ 6.Bxb2 fxg6 7.Ng5 Qxb2+ 8.Kg3 Qf2+ 9.Kxf2 Rxf6+ 10.exf6 Bxf6 11.Qxd5+ Kh8 12.Nf7+ Kh7 13.Qxd7 Rf8 14.Ke3 Ne7 15.Nd6 Nf5+ 16.Nxf5 Bg5+ 17.Kd3 gxf5 18.c4 Kg6 19.c5 Bf6 20.Qb7 Rh8 21.Nc3 Rh4 22.Nb5 Rh3+ 23.Kc4

-+ (-10.22 ++) Depth: 7/29 00:00:00 5kN
+- (7.11) Depth: 20/70 00:31:13 8372mN

[Terry McCracken]

Yes, that's the win and it's forced mate. 25..fg 26. Ng5! and after tossing pieces Black is mated.

Many programs miss the mate let alone Game 3-0.

White to play and mate in 10.

I don't belive it's a mate, eg. 26...Qbb2! 27.Bxb2 Qxb2+ 28.Kg3 Qf2+! 29.Kxf2 Rxf6+ 30.exf6 Bxf6 31.Qd5+ Kh8
No mate in sight!

That's a bad line. I can force mate. Don't believe me? We'll play it out. It's easy.

Computers have trouble with mate in this position, I find that a serious weakness.

It's a good test position.

[zullil]

Stockfish-2.0.1 (8 threads) about 3 hours:

Code: Select all

info depth 29 seldepth 41 multipv 1 score cp 808 time 10930907 nodes 99051119050 nps 9061564 pv d3h7 g8h7 f1h1 h7g8 h1h8 g8h8 d1h1 h8g8 g5g6 b6b2 c1b2 f7g6 f3g5 a1b2 g2g3 b2f2 g3f2 f8f6 e5f6 e7f6 h1d5 g8h8 g5f7 h8h7 d5d7 c6d8 f7d8 b8d8 d7h3 h7g8 h3e6 g8f8 b1d2 a5a4 f2f3 a4a3 d2c4 d8e8 e6d6 f8g8 c4a3

[Paloma]

From this position posted by Robert Flesher
[d]1r3rk1/3bbppp/1qn2P2/p2pP1P1/3P4/2PB1N2/6K1/qNBQ1R2 w - - 0 21
21. Bxh7+ Kxh7 22. Rh1+ Kg8 23. Rh8+ Kxh8 24. Qh1+ Kg8 25. g6!!
Winning! amazing test position!

we reach this position:
[d]1r3rk1/3bbpp1/1qn2PP1/p2pP3/3P4/2P2N2/6K1/qNB4Q b - - 0 25
you posted: Yes, that's the win and it's forced mate. 25..fg 26. Ng5! and after tossing pieces Black is mated.

after 25..fg 26. Ng5! we reach this position:
[d]1r3rk1/3bb1p1/1qn2Pp1/p2pP1N1/3P4/2P5/6K1/qNB4Q b - - 0 26
and now only 26...Qbb2! avoid mate! 27.Bxb2 Qxb2+ 28.Kg3 Qf2+! 29.Kxf2 Rxf6+ 30.exf6 Bxf6 31.Qd5+ +6.xx for white

second best move (26...Bh3+) leads after 27.Qxh3 to mate in 8 for white.

[Terry McCracken]

From this position posted by Robert Flesher
[d]1r3rk1/3bbppp/1qn2P2/p2pP1P1/3P4/2PB1N2/6K1/qNBQ1R2 w - - 0 21
21. Bxh7+ Kxh7 22. Rh1+ Kg8 23. Rh8+ Kxh8 24. Qh1+ Kg8 25. g6!!
Winning! amazing test position!

we reach this position:
[d]1r3rk1/3bbpp1/1qn2PP1/p2pP3/3P4/2P2N2/6K1/qNB4Q b - - 0 25
you posted: Yes, that's the win and it's forced mate. 25..fg 26. Ng5! and after tossing pieces Black is mated.

after 25..fg 26. Ng5! we reach this position:
[d]1r3rk1/3bb1p1/1qn2Pp1/p2pP1N1/3P4/2P5/6K1/qNB4Q b - - 0 26
and now only 26...Qbb2! avoid mate! 27.Bxb2 Qxb2+ 28.Kg3 Qf2+! 29.Kxf2 Rxf6+ 30.exf6 Bxf6 31.Qd5+ +6.xx for white

second best move (26...Bh3+) leads after 27.Qxh3 to mate in 8 for white.

Try not capturing with the Bishop. Try Nd2 instead.

[Robert Flesher]

From this position posted by Robert Flesher
[d]1r3rk1/3bbppp/1qn2P2/p2pP1P1/3P4/2PB1N2/6K1/qNBQ1R2 w - - 0 21
21. Bxh7+ Kxh7 22. Rh1+ Kg8 23. Rh8+ Kxh8 24. Qh1+ Kg8 25. g6!!
Winning! amazing test position!

we reach this position:
[d]1r3rk1/3bbpp1/1qn2PP1/p2pP3/3P4/2P2N2/6K1/qNB4Q b - - 0 25
you posted: Yes, that's the win and it's forced mate. 25..fg 26. Ng5! and after tossing pieces Black is mated.

after 25..fg 26. Ng5! we reach this position:
[d]1r3rk1/3bb1p1/1qn2Pp1/p2pP1N1/3P4/2P5/6K1/qNB4Q b - - 0 26
and now only 26...Qbb2! avoid mate! 27.Bxb2 Qxb2+ 28.Kg3 Qf2+! 29.Kxf2 Rxf6+ 30.exf6 Bxf6 31.Qd5+ +6.xx for white

second best move (26...Bh3+) leads after 27.Qxh3 to mate in 8 for white.

Try not capturing with the Bishop. Try Nd2 instead.

Hello Terry,


I think you may want to look at the postion again, or maybe I am looking at the wrong position. Either way, can you show the position in which you think nd2 is good?


In this position if nd2 ?? white gets mated not black.

[d]1r3rk1/3bb1p1/2n2Pp1/p2pP1N1/3P4/2P5/1q4K1/qNB4Q w - - 0 2

[Terry McCracken]

I will when I have more time. I have to make an appointment. I'll look at it again later today.

[Paloma]

Code: Select all

Try not capturing with the Bishop. Try Nd2 instead.

What?? 27.Nd2 Qxd2 28.Bxd2 Qxh1 and white lost his Queen!![/code]

[M ANSARI]

Engines are actually very good in these type of positions. Of course an extra queen can skew things for a while, but it doesn't take long for an engine to see the sac. But 5 minutes on fast hardware and R4.1 sees no mate.


New game
1r3rk1/3bbppp/1qn2P2/p2pP1P1/3P4/2PB1N2/6K1/qNBQ1R2 w - - 0 1

Analysis by Rybka 4.1 RC 2:

1.Qc2 g6 2.fxe7 Nxe7 3.Na3 Bf5 4.c4 Bxd3 5.Qxd3 Qb3 6.Qd2 dxc4
-+ (-9.69) Depth: 6 00:00:00 8kN
1.Nfd2 g6 2.fxe7 Nxe7 3.Rf6 Qd8 4.Qf3 Nf5 5.Kg1
-+ (-9.35) Depth: 6 00:00:00 20kN
1.Nfd2 g6 2.fxe7 Nxe7 3.Rf6 Qd8 4.Ba3 Qa2 5.Kg1 Bb5 6.Rd6
-+ (-9.37) Depth: 7 00:00:00 29kN
1.Nfd2 g6 2.fxe7 Nxe7 3.Rf6 Qd8 4.Ba3 Qa2 5.Qe2 Re8 6.c4 Be6
-+ (-9.39) Depth: 8 00:00:00 59kN
1.Nfd2 g6 2.fxe7 Nxe7 3.Rf6 Qb7 4.Ba6 Nf5 5.Qe1 Qc7 6.Ba3 Rfe8 7.Bd3 Qcxc3 8.Bxf5 Bxf5 9.Nxc3
-+ (-9.64) Depth: 9 00:00:00 126kN
1.Qe1 Qa2+ 2.Nbd2 Rfc8 3.Rh1 g6 4.e6 Bxe6 5.fxe7 Nxe7 6.Qh4 h5 7.gxh6 f6 8.h7+ Kf7 9.Re1 Rxc3 10.h8Q Rxh8 11.Qxh8 Rxd3 12.Qh6
-+ (-8.36) Depth: 9 00:00:02 1024kN
1.Qe1 g6 2.Qh4 Rfc8 3.fxe7 Nxe7 4.Rh1 h5 5.gxh6 Nf5 6.Qf2 Kh8 7.h7 Qe6 8.Ng5 Qe7 9.Bd2 Qb2 10.Bxf5 Bxf5 11.Kg3
-+ (-8.29) Depth: 10 00:00:04 2021kN
1.Qe1 g6 2.Qh4 Rfc8 3.fxe7 Nxe7 4.Rh1 h5 5.gxh6 Nf5 6.Qf2 Qe6 7.Bd2 Qb2 8.h7+ Kh8 9.Ng5 Qe7 10.Kg1 Qa2 11.Bxf5
-+ (-8.23) Depth: 11 00:00:05 2324kN
1.Qe1 g6 2.Qh4[] Rfc8 3.fxe7 Nxe7 4.Rh1[] h5 5.gxh6 Nf5 6.h7+ Kh8 7.Bxf5 Qa2+ 8.Kg3 gxf5 9.Bg5 Qg6 10.Nbd2 Rxc3 11.Kf4 Rb6 12.Bf6+ Rxf6 13.Qxf6+ Qxf6 14.exf6 Qc2 15.Rg1 Qd3 16.Rg8+
-+ (-7.86) Depth: 12 00:00:10 4152kN
1.Bxh7+ Kxh7 2.Rh1+ Kg8 3.Rh8+ Kxh8[] 4.Qh1+[] Kg8 5.fxg7 Kxg7 6.Qh6+[] Kg8[] 7.g6[] Qbb2+ 8.Bxb2 Qxb2+ 9.Nfd2 Bh3+ 10.Kxh3 fxg6 11.Qxg6+ Kh8 12.Qh6+[] Kg8 13.Qg6+ Kh8 14.Qh6+[] Kg8 15.Qg6+ Kh8 16.Qh6+[]
= (0.00) Depth: 12 00:00:14 6295kN
1.Bxh7+ Kxh7 2.Rh1+[] Kg8 3.Rh8+[] Kxh8[] 4.Qh1+[] Kg8 5.fxg7 Kxg7 6.Qh6+[] Kg8[] 7.g6[] Qbb2+ 8.Bxb2 Qxb2+ 9.Nbd2 Bh3+ 10.Kxh3 fxg6 11.Qxg6+ Kh8[] 12.Qh6+[] Kg8[] 13.Qg6+ Kh8[] 14.Qh6+[] Kg8[] 15.Qg6+ Kh8[] 16.Qh6+[]
= (0.00) Depth: 13 00:00:16 6982kN
1.Bxh7+ Kxh7 2.Rh1+[] Kg8 3.Rh8+[] Kxh8[] 4.Qh1+[] Kg8 5.g6 fxg6 6.Ng5 Qbb2+ 7.Bxb2 Rxb2+ 8.Kg3 Rg2+ 9.Kxg2 Bh3+ 10.Qxh3
= (0.12 !) Depth: 14 00:00:20 9109kN
1.Bxh7+ Kxh7 2.Rh1+[] Kg8 3.Rh8+[] Kxh8[] 4.Qh1+[] Kg8 5.g6 fxg6 6.Ng5 Qbb2+ 7.Bxb2
+/= (0.27 !) Depth: 14 00:00:21 9673kN
1.Bxh7+ Kxh7 2.Rh1+[] Kg8 3.Rh8+[] Kxh8[] 4.Qh1+[] Kg8 5.g6[] fxg6 6.Ng5[] Qab2+ 7.Bxb2 Qxb2+ 8.Kg3[] Qh2+ 9.Qxh2[]
+/= (0.67 !) Depth: 14 00:00:24 10562kN
1.Bxh7+ Kxh7 2.Rh1+[] Kg8 3.Rh8+[] Kxh8[] 4.Qh1+[] Kg8 5.g6[] fxg6 6.Ng5[]
+- (1.47 !) Depth: 14 00:00:27 12044kN
1.Bxh7+ Kxh7 2.Rh1+[] Kg8 3.Rh8+[] Kxh8[] 4.Qh1+[] Kg8 5.g6[] fxg6 6.Ng5
+- (3.07 !) Depth: 14 00:00:32 14156kN
1.Bxh7+ Kxh7 2.Rh1+[] Kg8 3.Rh8+[] Kxh8[] 4.Qh1+[] Kg8 5.g6[] fxg6 6.Ng5[] Qbb2+ 7.Bxb2[] Qxb2+ 8.Kg3[] Qf2+ 9.Kxf2[] Rxf6+ 10.exf6[] Bxf6 11.Qxd5+[] Kh8 12.Nf7+[] Kh7 13.Qxd7[] Nd8 14.Nxd8[] Rxd8 15.Qa7[] Rf8 16.Ke3
+- (4.88) Depth: 14 00:00:39 17866kN
1.Bxh7+ Kxh7 2.Rh1+[] Kg8[] 3.Rh8+[] Kxh8[] 4.Qh1+[] Kg8 5.g6[] Qbb2+ 6.Bxb2 Qxb2+ 7.Kg3 fxg6 8.Ng5 Qf2+ 9.Kxf2[] Rxf6+ 10.exf6[] Bxf6 11.Qxd5+ Kh8 12.Nf7+ Kh7 13.Qxd7[] Nd8 14.Nxd8[] Rxd8 15.Qa7[] Rf8 16.Ke3
+- (4.88) Depth: 15 00:00:50 23056kN
1.Bxh7+ Kxh7 2.Rh1+[] Kg8[] 3.Rh8+[] Kxh8[] 4.Qh1+[] Kg8 5.g6[] Qbb2+ 6.Bxb2 Qxb2+ 7.Kg3 fxg6 8.Ng5 Qf2+ 9.Kxf2[] Rxf6+ 10.exf6[] Bxf6 11.Qxd5+ Kh8 12.Nf7+ Kh7 13.Qxd7[] Nd8 14.Nxd8[] Rxd8 15.Qa7[] Rf8 16.Ke3
+- (5.00 !) Depth: 16 00:01:05 30051kN
1.Bxh7+ Kxh7 2.Rh1+[] Kg8[] 3.Rh8+[] Kxh8[] 4.Qh1+[] Kg8 5.g6[] Qbb2+ 6.Bxb2 Qxb2+ 7.Kg3 fxg6 8.Ng5 Qf2+ 9.Kxf2[] Rxf6+ 10.exf6[] Bxf6 11.Qxd5+ Kh8 12.Nf7+ Kh7 13.Qxd7[] Nd8 14.Nxd8[] Rxd8 15.Qa7[] Rf8 16.Ke3
+- (5.15 !) Depth: 16 00:01:20 36507kN
1.Bxh7+ Kxh7 2.Rh1+[] Kg8[] 3.Rh8+[] Kxh8[] 4.Qh1+[] Kg8 5.g6[] Qbb2+ 6.Bxb2[] Qxb2+ 7.Kg3[] fxg6 8.Ng5[] Qf2+ 9.Kxf2[] Rxf6+ 10.exf6[] Bxf6 11.Qxd5+[] Kh8 12.Nf7+[] Kh7 13.Qxd7[] Nd8 14.Nxd8[] Rxd8 15.Qa7[] Rf8 16.Ke3[]
+- (5.55 !) Depth: 16 00:01:46 47973kN, tb=1
1.Bxh7+ Kxh7 2.Rh1+[] Kg8 3.Rh8+[] Kxh8[] 4.Qh1+[] Kg8 5.g6[] Qbb2+ 6.Bxb2[] Qxb2+ 7.Kg3[] fxg6 8.Ng5[] Qf2+ 9.Kxf2[] Rxf6+ 10.exf6[] Bxf6 11.Qxd5+[] Kh8 12.Nf7+[] Kh7 13.Qxd7[] Nd8 14.Nxd8[] Rxd8 15.Qa7[] Rf8 16.Ke3[]
+- (5.59) Depth: 16 00:02:08 58263kN, tb=1
1.Bxh7+ Kxh7 2.Rh1+[] Kg8[] 3.Rh8+[] Kxh8[] 4.Qh1+[] Kg8 5.g6[] Qbb2+ 6.Bxb2[] Qxb2+ 7.Kg3[] fxg6 8.Ng5[] Qf2+ 9.Kxf2[] Rxf6+ 10.exf6[] Bxf6 11.Qxd5+[] Kh8 12.Nf7+[] Kh7 13.Qxd7[] Nd8 14.Nxd8[] Rxd8 15.Qa7[] Rf8 16.Ke3[]
+- (5.62) Depth: 17 00:02:56 80307kN, tb=3
1.Bxh7+ Kxh7 2.Rh1+[] Kg8 3.Rh8+[] Kxh8[] 4.Qh1+[] Kg8 5.g6[] Qbb2+ 6.Bxb2[] Qxb2+ 7.Kg3[] fxg6 8.Ng5[] Qf2+ 9.Kxf2[] Rxf6+ 10.exf6[] Bxf6 11.Qxd5+[] Kh8 12.Nf7+[] Kh7 13.Qxd7[] Nd8 14.Nxd8[] Rxd8 15.Qa7[] Rf8 16.Ke3[]
+- (6.01) Depth: 18 00:04:56 139mN, tb=17

(, Microsoft 01.03.2011)