Test Position, white to play and draw

[acase]

This one is difficult for engines and it is very clever.
All engines play the same first key move, but after that how does white draw?
I'll reveal the solution (unless someone else finds it) and the source later.


[fen]r5b1/7P/p6p/2B5/rp1R4/4N1P1/pk6/3K4 w - - 1 1[/fen]

[Hobacle]

This one is difficult for engines

But maybe it's easy for human solvers. It takes me about ten minutes to solve it.

Have to play 1.Rd2+ to stop the promotion.
Since 1...Ka1 and 1...Kc3 lead to a immediate mate and 1...Ka3/Kb3 2.Rd3+ Kb2 3.Rd2+ are a perpetual check, the only chance for Black is 1...Kb1.
Next, 2.Rb2+! Kxb2 3.h8Q are forced.
3...Kb1 is the only move for Black to keep the threat of promoting.
Then 4.Qa1+! Kxa1 5.Kc1.
5...b3 is forced to prevent Nc2# and Bd4# at the same time.
Finally it's clear: 6. Nc2+ bxc2 7.Be7!. Since 7...Rf4 will lose by 8.gxf4 and 7...Rf8 will fail by 8.Bxf8 Rg4 9.Ba3, 7...Rd4 8.Bf6 Rd8 9.Be5/Bg7/Bh8 are the draw.

I haven't tested it with engines. At least it's a great puzzle, thanks for bringing it here!

[peter]

This one is difficult for engines

But maybe it's easy for human solvers. It takes me about ten minutes to solve it.

Have to play 1.Rd2+ to stop the promotion.
Since 1...Ka1 and 1...Kc3 lead to a immediate mate and 1...Ka3/Kb3 2.Rd3+ Kb2 3.Rd2+ are a perpetual check, the only chance for Black is 1...Kb1.
Next, 2.Rb2+! Kxb2 3.h8Q are forced.
3...Kb1 is the only move for Black to keep the threat of promoting.
Then 4.Qa1+! Kxa1 5.Kc1.
5...b3 is forced to prevent Nc2# and Bd4# at the same time.
Finally it's clear: 6. Nc2+ bxc2 7.Be7!. Since 7...Rf4 will lose by 8.gxf4 and 7...Rf8 will fail by 8.Bxf8 Rg4 9.Ba3, 7...Rd4 8.Bf6 Rd8 9.Be5/Bg7/Bh8 are the draw.

I haven't tested it with engines. At least it's a great puzzle, thanks for bringing it here!

Yes, a very fine one indeed.
Even if latest Crystal has your solving- line almost at once, eval isn't getting somewhat near to the correct 0.00:


[fen]r5b1/7P/p6p/2B5/rp1R4/4N1P1/pk6/3K4 w - - 0 1[/fen]


Analysis by Crystal 040722:

1.Td2+ Kb1 2.Tb2+ Kxb2 3.h8D+ Kb1 4.Da1+ Kxa1 5.Kc1 b3 6.Sc2+ bxc2 7.Le7 Td4 8.Lf6 Tad8 9.Lh8 Lc4 10.Lf6 Ld3 11.Le5 Lh7 12.Lg7 T8d5 13.Lf6 Ld3 14.Lg7 Le2 15.Lh8 Lg4 16.Lg7 Lh3 17.Lf6 Le6 18.Lh8 Lf7 19.Lg7 Td8 20.Lf6 Le8 21.Le5 La4 22.Lg7 T8d6 23.Le5 h5 24.Lh8 T6d5 25.Lg7 Lb3 26.Lf6 Td6 27.Lh8 La4 28.Le5 Td8 29.Lf6 Lc6
Schwarz steht klar auf Gewinn: -+ (-8.04) Tiefe: 41/59 00:01:21 3127MN, tb=24857739

Letting it run for some longer won't help, I guess, Forward- Backward didn't neither and the output- line is correct as for the relevant moves anyhow, so why should the eval get better?

Once again the modification of Crystal's by user dorsz in OpenChess- forum called Crystallite has the right output- line together with 0.000- eval almost at once:

r5b1/7P/p6p/2B5/rp1R4/4N1P1/pk6/3K4 w - - 0 1

Analysis by Crystallite 1.1a-bmi2:

1.Td2+ Kb1 2.Tb2+ Kxb2 3.h8D+ Kb1 4.Df6 a1D 5.Ld4 Td8 6.Dxd8 Lb3+ 7.Ke1 Da3 8.Sf1
Schwarz steht klar auf Gewinn: -+ (-4.59) Tiefe: 10/19 00:00:00
...
1.Td2+ Kb1 2.Tb2+ Kxb2 3.h8D+ Kb1 4.Da1+ Kxa1 5.Kc1 b3 6.Sc2+ bxc2 7.Le7 Td4 8.Lf6 Tad8 9.Lg7 Le6 10.Lf6 Lf5 11.Lg7 a5 12.Lf6 h5 13.Lg7 Lc8 14.Le5 a4 15.Lf6 T8d5 16.Lg7
Schwarz steht klar auf Gewinn: -+ (-5.69) Tiefe: 17/51 00:00:01 62724kN
1.Td2+ Kb1 2.Tb2+ Kxb2 3.h8D+ Kb1 4.Da1+ Kxa1 5.Kc1 b3 6.Sc2+ bxc2 7.Le7 Td4 8.Lf6 Tad8 9.Lg7 Le6 10.Lf6 Lh3 11.Le5 a5 12.Lg7 Lc8 13.Le5 T8d7 14.Lh8 La6 15.Lf6 h5 16.Lh8
Schwarz steht klar auf Gewinn: -+ (-5.44) Tiefe: 18/51 00:00:01 63628kN
1.Td2+ Kb1 2.Tb2+ Kxb2 3.h8D+ Kb1 4.Da1+ Kxa1 5.Kc1 b3 6.Sc2+ bxc2 7.Le7 Td4 8.Lf6 Tad8 9.Lh8 T8d5 10.Lf6
Die Stellung ist ausgeglichen: = (0.00) Tiefe: 19/59 00:00:02 69121kN
...
1.Td2+ Kb1 2.Tb2+ Kxb2 3.h8D+ Kb1 4.Da1+ Kxa1 5.Kc1 b3 6.Sc2+ bxc2 7.Le7 Td4 8.Lf6 Tad8 9.Lh8 T8d5 10.Lf6
Die Stellung ist ausgeglichen: = (0.00) Tiefe: 44/39 00:01:32 3961MN

Crystallite had Syzygy Probe Limit 0, tbs can't help here anyhow, fortress arises far before tbs- positions, Crystal had another one try with Probe Limit 0 too, was just the same as the copied one with PL 6 above,
reagards

[acase]

The solution found is correct, this study is from 1999. Here is the link:

https://yacpdb.org/#275039/

[Ajedrecista]

Hello Andrew:

The solution found is correct, this study is from 1999. Here is the link:

https://yacpdb.org/#275039/

This one was easier to find at YACPDB. Author: Yuri Ivanovich Zemlyanski (ARVES link).

A nuissance: the black h-pawn is on h5 instead of h6 according to YACPDB, which does not change the beautiful solution. I could not find the original issue of the magazine to check out.

Regards from Spain.

Ajedrecista.

[Dariusz]

This one is difficult for engines and it is very clever.
All engines play the same first key move, but after that how does white draw?
I'll reveal the solution (unless someone else finds it) and the source later.


[fen]r5b1/7P/p6p/2B5/rp1R4/4N1P1/pk6/3K4 w - - 1 1[/fen]

Beauty study!

Attached is an analysis of Fire 8.NN.MC.3 (MacBook Pro M1, Hiarcs Chess Explorer Pro GUI).
The engine does not see the draw but only after 13 seconds it proposed an interesting continuation:

Fire 8.NN.MC.3, 139,9M nodes (2,4M nps), 1GB hash, 4 threads
0:00: -7.63/1 1.g4
0:00: -6.06/1 1.Bxb4
0:00: -3.13/1 1.hxg8=Q
0:00: -5.32/2 1.hxg8=Q Rxg8
0:00: -5.10/2 1.h8=Q Bb3+
0:00: -2.55/2 1.Rd2+ Kb1
0:00: -3.11/3 1.Rd2+ Kb1 2.h8=Q
0:00: -3.20/4 1.Rd2+ Kb1
0:00: -3.29/4 1.Rd2+ Kb1
0:00: -3.09/4 1.Rd2+
0:00: -2.96/4 1.Rd2+
0:00: -2.54/4 1.Rd2+
0:00: -1.70/4 1.Rd2+
0:00: -3.26/4 1.Rd2+ Kb1
0:00: -3.43/4 1.Rd2+ Kb1
0:00: -3.59/4 1.Rd2+ Kb1 2.Bd4 Bb3+
0:00: -3.68/5 1.Rd2+ Kb1
0:00: -3.49/5 1.Rd2+
0:00: -3.41/5 1.Rd2+
0:00: -3.13/5 1.Rd2+
0:00: -2.91/5 1.Rd2+
0:00: -2.65/5 1.Rd2+
0:00: -2.37/5 1.Rd2+
0:00: -2.00/5 1.Rd2+
0:00: -1.59/5 1.Rd2+
0:00: -1.58/5 1.Rd2+ Kb1 2.Rb2+ Kxb2 3.Bd4+
0:00: -1.42/6 1.Rd2+
0:00: -1.27/6 1.Rd2+
0:00: -1.18/6 1.Rd2+
0:00: -1.05/6 1.Rd2+
0:00: -1.40/6 1.Rd2+ Kb1
0:00: -1.56/6 1.Rd2+ Kb1
0:00: -1.87/6 1.Rd2+ Kb1
0:00: -2.19/6 1.Rd2+ Kb1
0:00: -1.30/6 1.Rd2+
0:00: -2.26/6 1.Rd2+ Kb1
0:00: -1.79/6 1.Rd2+ Kb1 2.Rb2+ Kxb2 3.h8=Q+ Kb3
0:00: -1.84/7 1.Rd2+ Kb1
0:00: -1.90/7 1.Rd2+ Kb1
0:00: -1.98/7 1.Rd2+ Kb1
0:00: -2.10/7 1.Rd2+ Kb1
0:00: -2.23/7 1.Rd2+ Kb1
0:00: -2.50/7 1.Rd2+ Kb1
0:00: -2.77/7 1.Rd2+ Kb1
0:00: -3.07/7 1.Rd2+ Kb1
0:00: -3.50/7 1.Rd2+ Kb1
0:00: -4.01/7 1.Rd2+ Kb1
0:00: -3.51/7 1.Rd2+
0:00: -4.12/7 1.Rd2+ Kb1
0:00: -3.07/7 1.Rd2+
0:00: -4.30/7 1.Rd2+ Kb1
0:00: -5.97/7 1.Rd2+ Kb1
0:00: -4.42/7 1.Rd2+
0:00: -6.32/7 1.Rd2+ Kb1
0:00: -6.20/7 1.Bxb4 Be6 2.Ke1 Kb3 3.h8=Q a1=Q+ 4.Ke2 Qb2+ 5.Ke1 Ra1+
0:00: -6.13/8 1.Bxb4
0:00: -6.08/8 1.Bxb4
0:00: -5.96/8 1.Bxb4
0:00: -5.81/8 1.Bxb4
0:00: -5.65/8 1.Bxb4
0:00: -5.45/8 1.Bxb4
0:00: -5.21/8 1.Bxb4
0:00: -5.60/8 1.Bxb4 Be6
0:00: -4.06/8 1.hxg8=Q
0:00: -3.58/8 1.hxg8=Q
0:00: -4.57/8 1.hxg8=Q Rxg8
0:00: -3.72/8 1.hxg8=Q
0:00: -3.38/8 1.hxg8=Q Rxg8 2.Rd2+ Kb1 3.Nc4 Rg4 4.Ne5 Rxg3 5.Nd3
0:00: -3.49/9 1.hxg8=Q Rxg8
0:00: -3.56/9 1.hxg8=Q Rxg8
0:00: -3.66/9 1.hxg8=Q Rxg8
0:00: -3.89/9 1.hxg8=Q Rxg8
0:00: -4.11/9 1.hxg8=Q Rxg8
0:00: -4.36/9 1.hxg8=Q Rxg8
0:00: -4.46/9 1.hxg8=Q Rxg8
0:00: -4.80/9 1.hxg8=Q Rxg8
0:00: -4.44/9 1.hxg8=Q
0:00: -4.91/9 1.hxg8=Q Rxg8
0:00: -5.57/9 1.hxg8=Q Rxg8
0:00: -4.00/9 1.Rd2+
0:00: -4.97/9 1.Rd2+ Kb1
0:00: -4.06/9 1.Rd2+
0:00: -2.68/9 1.Rd2+
0:00: -3.15/9 1.Rd2+ Kb1 2.Rb2+ Kxb2 3.h8=Q+ Kb1 4.Nc2 a1=Q 5.Qxh6 Rd8+ 6.Bd6 Kb2+ 7.Nxa1
0:00: -3.20/10 1.Rd2+ Kb1
0:00: -3.32/10 1.Rd2+ Kb1
0:00: -3.51/10 1.Rd2+ Kb1
0:00: -3.63/10 1.Rd2+ Kb1
0:00: -3.83/10 1.Rd2+ Kb1
0:00: -4.08/10 1.Rd2+ Kb1
0:00: -4.35/10 1.Rd2+ Kb1
0:00: -4.69/10 1.Rd2+ Kb1
0:00: -5.14/10 1.Rd2+ Kb1
0:00: -5.61/10 1.Rd2+ Kb1
0:00: -5.05/10 1.Rd2+
0:00: -4.14/10 1.Rd2+
0:00: -2.99/10 1.Rd2+
0:00: -2.99/10 1.Rd2+ Kb1 2.Rb2+ Kxb2 3.h8=Q+ Kb1 4.Qa1+ Kxa1 5.Kc1 b3 6.Nc2+ bxc2 7.Be7 Rd8
0:00: -3.17/11 1.Rd2+ Kb1
0:00: -2.99/11 1.Rd2+
0:00: -2.89/11 1.Rd2+
0:00: -2.70/11 1.Rd2+
0:00: -2.56/11 1.Rd2+
0:00: -2.74/11 1.Rd2+ Kb1
0:00: -2.53/11 1.Rd2+
0:00: -2.19/11 1.Rd2+
0:00: -2.71/11 1.Rd2+ Kb1
0:00: -2.12/11 1.Rd2+
0:00: -2.71/11 1.Rd2+ Kb1
0:00: -2.07/11 1.Rd2+
0:00: -1.01/11 1.Rd2+
0:00: -1.94/11 1.Rd2+ Kb1
0:00: -3.63/11 1.Rd2+ Kb1
0:00: -4.34/11 1.Rd2+ Kb1 2.Rb2+ Kxb2 3.h8=Q+ Kb1 4.Qa1+ Kxa1 5.Kc1 b3 6.Nc2+ bxc2 7.Be7
0:00: -4.25/12 1.Rd2+
0:00: -4.18/12 1.Rd2+
0:00: -4.08/12 1.Rd2+
0:00: -3.97/12 1.Rd2+
0:00: -3.76/12 1.Rd2+
0:00: -3.53/12 1.Rd2+
0:00: -3.26/12 1.Rd2+
0:00: -2.92/12 1.Rd2+
0:00: -3.26/12 1.Rd2+ Kb1
0:00: -3.77/12 1.Rd2+ Kb1
0:00: -4.59/12 1.Rd2+ Kb1
0:00: -5.42/12 1.Rd2+ Kb1
0:00: -6.48/12 1.Rd2+ Kb1
0:00: -5.16/12 1.Rd2+
0:00: -3.48/12 1.Rd2+
0:00: -5.08/12 1.Rd2+ Kb1
0:00: -6.22/12 1.Rd2+ Kb1 2.Rb2+ Kxb2 3.h8=Q+ Kb1 4.Qf6 a1=Q 5.Bd4 Bb3+ 6.Ke1 Qa2 7.Qe7 Bc2 8.Kf2 Bd3+ 9.Kg1 Qe2 10.Qb7 Qe1+ 11.Kh2 Qc1 12.Qxa8 Ra2+ 13.Kh3 Bf1+ 14.Nxf1
0:00: -6.27/13 1.Rd2+ Kb1
0:00: -6.32/13 1.Rd2+ Kb1
0:00: -5.96/13 1.Rd2+
0:00: -6.33/13 1.Rd2+ Kb1
0:00: -6.46/13 1.Rd2+ Kb1
0:00: -6.65/13 1.Rd2+ Kb1
0:00: -6.89/13 1.Rd2+ Kb1
0:00: -6.61/13 1.Rd2+
0:00: -6.94/13 1.Rd2+ Kb1
0:00: -6.48/13 1.Rd2+
0:00: -5.82/13 1.Rd2+
0:00: -6.42/13 1.Rd2+ Kb1
0:00: -7.47/13 1.Rd2+ Kb1
0:00: -6.57/13 1.Rd2+
0:00: -7.69/13 1.Rd2+ Kb1
0:00: -6.13/13 1.Rd2+
0:01: -8.04/13 1.Rd2+ Kb1
0:01: -5.74/13 1.Rd2+
0:01: -8.09/13 1.Rd2+ Kb1 2.Rb2+ Kxb2 3.h8=Q+ Kb1 4.Qf6 a1=Q 5.Bd4 Bb3+ 6.Ke1 Qa2 7.Kf1 Qd2 8.Kg1 Ka2 9.Nf1 Qc2 10.Qe5 Qd1 11.Qe4 Qc2 12.Qxa8
0:01: -8.00/14 1.Rd2+
0:01: -8.09/14 1.Rd2+ Kb1
0:01: -8.00/14 1.Rd2+
0:01: -7.81/14 1.Rd2+
0:01: -7.59/14 1.Rd2+
0:01: -7.31/14 1.Rd2+
0:01: -7.07/14 1.Rd2+
0:01: -6.69/14 1.Rd2+
0:01: -6.00/14 1.Rd2+
0:01: -6.69/14 1.Rd2+ Kb1
0:01: -7.36/14 1.Rd2+ Kb1
0:01: -8.19/14 1.Rd2+ Kb1
0:01: -7.41/14 1.Rd2+
0:01: -6.08/14 1.Rd2+
0:01: -5.36/14 1.Rd2+ Kb1 2.Rb2+ Kxb2 3.h8=Q+ Kb1 4.Qf6 a1=Q 5.Bd4 Bb3+ 6.Ke1 Qa2 7.Qf5+ Bc2 8.Qf1 Rd8 9.Kf2+ Bd1+ 10.Kg1 Rxd4 11.Nxd1 Qd2 12.Nc3+ Kc2 13.Nxa4 b3
0:01: -5.42/15 1.Rd2+ Kb1
0:01: -5.48/15 1.Rd2+ Kb1
0:01: -5.65/15 1.Rd2+ Kb1
0:01: -5.76/15 1.Rd2+ Kb1
0:01: -5.92/15 1.Rd2+ Kb1
0:01: -6.11/15 1.Rd2+ Kb1
0:01: -6.43/15 1.Rd2+ Kb1
0:01: -6.81/15 1.Rd2+ Kb1
0:01: -7.22/15 1.Rd2+ Kb1
0:01: -7.73/15 1.Rd2+ Kb1
0:01: -8.39/15 1.Rd2+ Kb1
0:01: -7.69/15 1.Rd2+
0:01: -8.53/15 1.Rd2+ Kb1
0:01: -7.53/15 1.Rd2+
0:01: -5.82/15 1.Rd2+
0:01: -6.32/15 1.Rd2+ Kb1 2.Rb2+ Kxb2 3.h8=Q+ Kb1 4.Qf6 a1=Q 5.Bd4 Bb3+ 6.Ke1 Qa2 7.Qf5+ Bc2 8.Qf1 Rd8 9.Kf2+ Bd1+ 10.Kg1 Rxd4 11.Nxd1 Qc2 12.Nc3+ Kb2 13.Nxa4+ Qxa4 14.Qf2+ Kc1 15.Qxd4
0:01: -6.37/16 1.Rd2+ Kb1
0:01: -6.41/16 1.Rd2+ Kb1
0:01: -6.49/16 1.Rd2+ Kb1
0:01: -6.59/16 1.Rd2+ Kb1
0:01: -6.72/16 1.Rd2+ Kb1
0:01: -6.91/16 1.Rd2+ Kb1
0:01: -7.15/16 1.Rd2+ Kb1
0:01: -7.47/16 1.Rd2+ Kb1
0:01: -7.87/16 1.Rd2+ Kb1
0:01: -8.39/16 1.Rd2+ Kb1
0:02: -8.63/16 1.Rd2+ Kb1 2.Bd4 a1=Q 3.Bxa1 Rxa1 4.hxg8=Q Rxg8 5.Nc4 Ra2 6.Rd3 Rb2 7.Rd4 a5 8.Re4 Rd8+ 9.Ke1 Rd3 10.Nxb2 Kxb2 11.Re2+ Kc1
0:02: -8.68/17 1.Rd2+ Kb1
0:02: -8.63/17 1.Rd2+
0:02: -8.62/17 1.Rd2+ Kb1 2.Bd4 a1=Q 3.Bxa1 Rxa1 4.hxg8=Q Rxg8 5.Nc4 Ra2 6.Rd3 Rb2 7.Nxb2 Kxb2 8.Rd2+ Kb1 9.Rd5 Rxg3 10.Kd2
0:02: -8.57/18 1.Rd2+
0:02: -8.52/18 1.Rd2+
0:02: -8.45/18 1.Rd2+
0:02: -8.35/18 1.Rd2+
0:03: -8.21/18 1.Rd2+
0:03: -8.03/18 1.Rd2+
0:03: -8.17/18 1.Rd2+ Kb1
0:03: -7.98/18 1.Rd2+
0:03: -8.23/18 1.Rd2+ Kb1
0:05: -8.75/18 1.Rd2+ Kb1
0:05: -8.44/18 1.Rd2+ Kb1 2.Bd4 a1=Q 3.Bxa1 Rxa1 4.hxg8=R Rxg8 5.Nc4 Ra2 6.Rd3 Rc8 7.Rb3+ Ka1 8.Rxb4 a5 9.Nxa5 Rxa5 10.Rb6 Rd5+ 11.Ke2 Rh5 12.Kf3 Rc4 13.Ra6+ Kb1 14.Rb6+ Kc2 15.Rc6 Rxc6 16.Kg4 Rg5+ 17.Kf3 Rc4 18.Kf2
0:05: -8.49/19 1.Rd2+ Kb1
0:05: -8.53/19 1.Rd2+ Kb1
0:06: -8.60/19 1.Rd2+ Kb1
0:06: -8.54/19 1.Rd2+
0:06: -8.41/19 1.Rd2+
0:06: -8.51/19 1.Rd2+ Kb1
0:06: -8.75/19 1.Rd2+ Kb1
0:08: -8.56/19 1.Rd2+
0:08: -8.40/19 1.Rd2+ Kb1 2.Bd4 a1=Q 3.Bxa1 Rxa1 4.hxg8=R Rxg8 5.Nc4 Ra2 6.Rd3 Rc8 7.Rb3+ Ka1 8.Rxb4 a5 9.Nxa5 Rxa5 10.Kd2 Rc6 11.Ke3 Rc3+ 12.Kf4 Ka2 13.Kg4 Ka3 14.Rb6 Rc4+ 15.Kf3 Rh5 16.Ra6+ Kb4 17.Kg2
0:08: -8.35/20 1.Rd2+
0:09: -8.40/20 1.Rd2+ Kb1
0:09: -8.47/20 1.Rd2+ Kb1
0:09: -8.41/20 1.Rd2+
0:09: -8.27/20 1.Rd2+
0:09: -8.38/20 1.Rd2+ Kb1
0:09: -8.23/20 1.Rd2+
0:10: -8.42/20 1.Rd2+ Kb1
0:10: -8.17/20 1.Rd2+
0:11: -8.50/20 1.Rd2+ Kb1
0:11: -8.07/20 1.Rd2+
0:11: -8.07/20 1.Rd2+ Kb1 2.Rb2+ Kxb2 3.h8=Q+ Kb1 4.Qa1+ Kxa1 5.Kc1 b3 6.Nc2+ bxc2 7.Be7 Rd4 8.Bf6 Rd8 9.g4 Bc4 10.g5 hxg5 11.Bg7 Rd5 12.Bf6 a5 13.Bg7 Bb5 14.Bf6 Bd3 15.Bg7 Rd8 16.Bf6 Bc4 17.Be5
0:12: -8.12/21 1.Rd2+ Kb1
0:12: -8.16/21 1.Rd2+ Kb1
0:13: -8.23/21 1.Rd2+ Kb1
0:13: -8.33/21 1.Rd2+ Kb1
0:13: -8.35/21 1.Rd2+ Kb1 2.Rb2+ Kxb2 3.h8=Q+ Kb1 4.Qa1+ Kxa1 5.Kc1 b3 6.Nc2+ bxc2 7.Be7 Rd4 8.Bf6 Rd8 9.Bg7 Bc4 10.Be5 Bd3 11.Bf6 Rd6 12.Bg7 Bb5 13.Bh8 Bc4 14.Be5 Be2 15.Bh8 Rd8 16.Bg7 Rd7 17.Be5
0:13: -8.35/22 1.Rd2+ Kb1 2.Rb2+ Kxb2 3.h8=Q+ Kb1 4.Qa1+ Kxa1 5.Kc1 b3 6.Nc2+ bxc2 7.Be7 Rd4 8.Bf6 Rd8 9.Bg7 Bc4 10.Be5 Bd3 11.Bf6 Rd6 12.Bg7 Bb5 13.Bh8 Bc4 14.Be5 Bb3 15.Bg7 Rd5 16.Bh8 Bc4 17.Bf6 Be2 18.Bg7 Rd6 19.Be5
0:14: -8.35/23 1.Rd2+ Kb1 2.Rb2+ Kxb2 3.h8=Q+ Kb1 4.Qa1+ Kxa1 5.Kc1 b3 6.Nc2+ bxc2 7.Be7 Rd4 8.Bf6 Rd8 9.Bg7 Bc4 10.Be5 Bd3 11.Bf6 Rd6 12.Bg7 Rd5 13.Bh8 Bc4 14.Bf6 Be2 15.Bg7 Rd8 16.Be5 Rd7 17.Bh8 Rd6 18.Be5 Rd8 19.Bg7 Rd5 20.Bh8 Bd3 21.Bf6
0:15: -8.35/24 1.Rd2+ Kb1 2.Rb2+ Kxb2 3.h8=Q+ Kb1 4.Qa1+ Kxa1 5.Kc1 b3 6.Nc2+ bxc2 7.Be7 Rd4 8.Bf6 Rd8 9.Bg7 Bc4 10.Be5 Bd3 11.Bf6 Rd6 12.Bg7 Rd5 13.Bh8 Bc4 14.Bf6 Rd6 15.Bg7 Bb3 16.Be5 Be6 17.Bg7 Bg4 18.Bh8 Bf5 19.Bg7 Rd8 20.Bf6 Be6 21.Be5 Bb3 22.Bf6
0:21: -8.35/25 1.Rd2+ Kb1 2.Rb2+ Kxb2 3.h8=Q+ Kb1 4.Qa1+ Kxa1 5.Kc1 b3 6.Nc2+ bxc2 7.Be7 Rd4 8.Bf6 Rd8 9.Bg7 Bc4 10.Be5 Bd3 11.Bf6 Rd6 12.Bg7 Rd5 13.Bh8 Bb5 14.Bf6 Be2 15.Bg7 Bc4 16.Bf6 Rd6 17.Bg7 Bb3 18.Be5 Be6 19.Bg7 Bc4 20.Be5 Rd8 21.Bg7
0:27: -8.35/26 1.Rd2+ Kb1 2.Rb2+ Kxb2 3.h8=Q+ Kb1 4.Qa1+ Kxa1 5.Kc1 b3 6.Nc2+ bxc2 7.Be7 Rd4 8.Bf6 Rd8 9.Bg7 Bc4 10.Be5 Bd3 11.Bf6 Rd6 12.Bg7 Rd5 13.Bh8 Be2 14.Bg7 Bd1 15.Bf6 Bg4 16.Bg7 Be2 17.Bf6 Bc4 18.Bh8 Rd6 19.Be5 Bb3 20.Bg7 Rd5 21.Bh8
0:30: -8.35/27 1.Rd2+ Kb1 2.Rb2+ Kxb2 3.h8=Q+ Kb1 4.Qa1+ Kxa1 5.Kc1 b3 6.Nc2+ bxc2 7.Be7 Rd4 8.Bf6 Rd8 9.Bg7 Bc4 10.Be5 Bd3 11.Bf6 Rd6 12.Bg7 Rd5 13.Bh8 Be2 14.Bf6 Bc4 15.Bh8 Bd3 16.Bg7 Rd6 17.Be5 Be2 18.Bh8 Bb5 19.Bg7 Rd7 20.Be5 Rd8 21.Bf6 Bd3 22.Be5
0:45: -8.35/28 1.Rd2+ Kb1 2.Rb2+ Kxb2 3.h8=Q+ Kb1 4.Qa1+ Kxa1 5.Kc1 b3 6.Nc2+ bxc2 7.Be7 Rd4 8.Bf6 Rd8 9.Bg7 Bc4 10.Be5 Bd3 11.Bf6 Rd6 12.Bg7 Rd5 13.Bh8 Be2 14.Bf6 Bc4 15.Bh8 Bd3 16.Bg7 Rd6 17.Be5 Be2 18.Bh8 Bc4 19.Bg7 Rd7 20.Be5 Rd8 21.Bg7 Bb3 22.Be5 Rd5 23.Bh8

[acase]

Hello Andrew:

The solution found is correct, this study is from 1999. Here is the link:

https://yacpdb.org/#275039/

This one was easier to find at YACPDB. Author: Yuri Ivanovich Zemlyanski (ARVES link).

A nuissance: the black h-pawn is on h5 instead of h6 according to YACPDB, which does not change the beautiful solution. I could not find the original issue of the magazine to check out.

Regards from Spain.

Ajedrecista.

Hello,

I actually intentionally misplaced that pawn so nobody could look up the solution, I figured someone or some engine would be able to solve it but, I wanted them to do it without seeing the solution first. Of course I tested it to make sure it still worked correctly.

[acase]

Here is the original pgn:

[pgn][Event "sp.p Tsjechover-90 MT Shakhmaty Peterbu"]
[Site "?"]
[Date "1999.??.??"]
[Round "?"]
[White "Zemljanski=Y"]
[Black "[=0741.24d1b2"]
[Result "1/2-1/2"]
[TimeControl "300+3"]
[SetUp "1"]
[FEN "r5b1/7P/p7/2B4p/rp1R4/4N1P1/pk6/3K4 w - - 0 1"]
[Termination "normal"]
[PlyCount "17"]
[WhiteType "human"]
[BlackType "human"]

1. Rd2+ (1. Rxb4+ $2 Rxb4 2. h8=Q+ Kb1 3. Qc3 Rd8+ 4. Ke2 Rb2+ 5. Kf3 Rdd2
6. Nf1 Rd1 7. Ne3 a1=Q 8. Nxd1 Rb3) 1. .. Kb1 2. Rb2+ Kxb2 3. h8=Q+ Kb1 (3.
.. Kb3 4. Nc2) 4. Qa1+ (4. Nc2 $2 a1=Q 5. Nxa1 Bb3+ 6. Nxb3 Rxh8) 4. ..
Kxa1 5. Kc1 b3 6. Nc2+ bxc2 7. Be7 Rd4 (7. .. Rf8 $2 8. Bxf8 Rg4 9. Ba3 Rb4
10. Bxb4) 8. Bf6 Rd8 9. Bh8 1/2-1/2[/pgn]

[Hobacle]

I actually intentionally misplaced that pawn so nobody could look up the solution

What about that rook?


[fen]r5b1/7P/p4R2/2B4p/rp6/4N1P1/pk6/3K4 w - - 0 1[/fen]

[peter]

I actually intentionally misplaced that pawn so nobody could look up the solution

What about that rook?


[fen]r5b1/7P/p4R2/2B4p/rp6/4N1P1/pk6/3K4 w - - 0 1[/fen]

Not working anymore, or do you have anything better for White then this?

r5b1/7P/p4R2/2B4p/rp6/4N1P1/pk6/3K4 w - - 0 1

Analysis by Crystallite 1.1a-bmi2:

1.Bd4+ Kb3 2.h8Q a1R+ 3.Bxa1 Rxa1+ 4.Kd2 Rd8+ 5.Nd5 Rxd5+ 6.Ke3 Be6 7.Kf2 Ra2+ 8.Kf3 Rd1 9.Kf4 Bc4 10.Kg5 Rd3 11.Qb8 Rg2 12.Kh6 Rdxg3 13.Qd6 Rd3 14.Qe5 Rc3 15.Rb6 Ra2 16.Qxh5 a5 17.Kg7 a4 18.Kf6 Rf2+ 19.Ke7 Re2+ 20.Kf6 Rce3 21.Qh1 Re1 22.Qh2 Re6+ 23.Rxe6 Rxe6+ 24.Kg7 a3 25.Qd2 a2 26.Qd1+ Ka3 27.Qc1+ Ka4 28.Qd1+ b3 29.Qd7+ Kb4 30.Qd2+ Kb5 31.Qg5+ Ka4 32.Qc1 Re7+ 33.Kh6 Re4 34.Kg7 Be2 35.Qc6+ Ka3 36.Qc1+ Kb4 37.Qd2+ Ka4 38.Qb2 Rc4 39.Kh6 Bf3 40.Kg7 Kb4 41.Kf6 Rc6+ 42.Kg7 Rc3 43.Qa1 Bd5 44.Qb2 Bc4 45.Kf8 Rc2 46.Qe5 a1Q
Black is clearly winning: -+ (-6.35 ++) Depth: 40/91 00:11:37 28813MN, tb=187071955

Output after some Forward (with the one and another one wrongly drawing line yet too)- Backward,
regards