13 hard test positions July 2016

[Vinvin]

Some new positions from a couple of months, verified but may be not enough :

1)
b4!
[d]2kr3r/1p3pb1/pBnqp2p/P2p2p1/8/2PB4/1P3PPP/R2Q1RK1 w - - bm b4;

2)
Winning moves : 1.a8=Q or =R
[pgn]
[Event "1.hm Ceskoslovensky Sach#657 @3"]
[Site "?"]
[Date "1995.??.??"]
[Round "?"]
[White "Solovyov=Y"]
[Black "(+3025.33h5a6)"]
[Result "1-0"]
[SetUp "1"]
[FEN "6q1/PpB5/k7/P6K/6n1/1P4p1/5p2/1B3N1N w - - 0 1"]
[PlyCount "23"]
[EventDate "1995.??.??"]

{Ceskoslovensky Sach/8 EG#11148 @3: EG=132 4/1999} 1. a8=Q+ Qxa8 2. Bd3+ Ka7 3.
Bb6+ Kb8 4. Kxg4 g2 5. Nhg3 g1=Q 6. Kf3 $1 (6. Kh3 $2 Kc8 7. Bf5+ Kb8 8. Be6
Qa6 9. Bc4 Qxc4) 6... Kc8 7. Bf5+ Kb8 8. Be6 Qa6 9. Bc4 Qa8 (9... Qxb6 $1 {
<cook>} 10. axb6 Kc8) 10. b4 Kc8 11. Be6+ Kb8 12. b5 1-0
[/pgn]


3)
How much time to find 16. Bg5! (after 15...d5?) with a very good advantage ( >0.50) ?
From the match Polgar - Spassky (1993) Round 8.

[d]r2qrbk1/1bpn1p1p/p4np1/1p1pp3/3PP3/1PP2NNP/P1B2PP1/R1BQR1K1 w - - 0 16

[pgn]
[Event "Polgar - Spassky"]
[Site "Budapest HUN"]
[Date "1993.02.12"]
[Round "8"]
[White "Judit Polgar"]
[Black "Boris Spassky"]
[Result "1-0"]
[ECO "C95"]
[Opening "Spanish"]
[Variation "Closed, Breyer, Main Line, 14.Ng3 g6 15.b3"]

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8.
c3 O-O 9. h3 Nb8 10. d4 Nbd7 11. Nbd2 Bb7 12. Bc2 Re8 13. Nf1 Bf8 14. Ng3
g6 15. b3 d5 16. Bg5 h6 17. Bh4 dxe4 18. Nxe4 g5 19. dxe5 Nxe4
20. Bxe4 Bxe4 21. Rxe4 gxh4 22. Rd4 Re7 23. e6 fxe6
24. Ne5 Rg7 25. Rxd7 Qg5 26. Qf3 Rd8 27. Rxg7+ Qxg7 28. Re1 Bc5 29. Ng4 Qg6
30. Qf4 Bb6 31. Nxh6+ Kg7 32. Qxh4 Qf6 33. Qxf6+ Kxf6 34. Re2 Rd1+ 35. Kh2
Rc1 36. g4 Rxc3 37. h4 Rd3 38. g5+ Ke7 39. g6 Kf8 40. Rxe6 Rf3
41. Ng4 Rf5 42. Kg3 1-0
[/pgn]

4)
From the Chessbase site, a position with a lot of zugzwang :
[pgn]
[Event "1.p Magyar Sakkvilág"]
[Site "?"]
[Date "2006.??.??"]
[Round "?"]
[White "Benno, Pal"]
[Black "White to play and win"]
[Result "1-0"]
[WhiteElo "2000"]
[TimeControl "7200+15"]
[SetUp "1"]
[FEN "q7/7R/k7/1p6/1p6/1P2B3/7K/8 w - - 0 1"]
[Termination "normal"]
[PlyCount "43"]
[WhiteType "program"]
[BlackType "human"]

{The thing which really confuses me in such positions is how to calculate.
You clearly need to think long term in such situation, figure out the
different setups and which ones will get Black into a zugwang. But while
doing that it is easy to enter into a dream world and blunder into a simple
tactic. Hence, while the first priority is long term strategic thinking, it
is extremely important to be tactically vigilant. This is what the absolute
elite excel in.} 1. Bd4 {Just improving the position of the bishop,
controlling the g7 square. One thing is clear: White cannot ever sacrifice
his rook and bishop for the queen. The pawn endgame would be drawn even if
the white king is too close to the black pawns. Hence, White has to make
Black give up his queen for the rook or to checkmate the black king.} Qb8+
2. Kh1 {$1 You can find this move through the process of elimination.} (2.
Kg2 {$4 loses quickly to} 2. .. Qg8+ 3. Rg7 Qd5+ 4. Kf1 Qxd4 $19) (2. Kh3
Qc8+ 3. Kg3 (3. Kh2 Qc2+ $19) 3. .. Qg8+ 4. Rg7 Qb8+ 5. Kg2 Qa8+ {and the
rain of checks will not end.}) 2. .. Qa8+ 3. Kg1 {The only way to start
making progress. White aims to get his king on the queenside. It will be a
long treacherous route, but that is the only way to play for a win.} Qg8+
(3. .. Qb8 {is possible but really doesn't make such a huge difference.})
4. Rg7 Qb8 5. Kg2 (5. Kf2 {Once again moving too quickly will ruin
everything} Qf4+ {$1 $19}) 5. .. Qa8+ 6. Kf2 Qb8 (6. .. Qf8+ 7. Ke3 Qe8+ 8.
Kd2 {And the queen will have to return back to the the defence of the a7
square.}) 7. Ke3 Qe8+ (7. .. Qa8 8. Kd2 {$1 $18 The main line will explain
you why this is winning.}) 8. Kd3 Qb8 (8. .. Qa8 {This move loses in the
same fashion as the main line.} 9. Rf7 {$1 $18}) 9. Rg6+ $1 (9. Kc2 Qh2+
{$11 We don't really want to the queen to get activated by entering our
territory. This will end in a draw.}) 9. .. Ka5 (9. .. Kb7 10. Rb6+ $18)
10. Rg1 $1 Ka6 {Now if the black queen was on b7 it would be Ra1 mate.} 11.
Rg7 {The main idea of this manoeuvre was to force the black queen to a8.}
Qa8 12. Rf7 {$1 This is an important subtlety. Why does the rook need to be
on the f-file, as opposed to the g-file? Because the bishop can then block
the check on the second rank, for instance after Qh2+ or Qg2+ by Bf2!} Qb8
13. Kc2 $1 Qa8 (13. .. Qh2+ 14. Bf2 {$18 is the neat point. The winning
line is same as the main line.}) 14. Kb2 Qg2+ 15. Bf2 {$1 Ahh, that's the
reason: the bishop can block the check because it is protected by the rook
on f7! The queen has to return to its thankless job of defending the a7
square.} Qa8 {Now that we have safely smuggled our king to the queenside
all that remains to make the final preparations. The important thing is not
to let the Black queen activate herself.} 16. Rh7 {$1 Taking the h2 and h8
square under control.} Qb8 17. Bd4 {The bishop takes the e5 square under
control. What beautiful co-ordination.} Qa8 18. Ka1 {$1 From h1 to a1! This
journey of the king has made sure that White will win this game.} Qb8 19.
Rh6+ {$1 The key part where you have to stop thinking strategically and put
on your tactical thinking caps and find the win.} Ka5 {and now White can
force the queen onto b7, where it blocks a vital escape square for the
black king.} 20. Rh8 {$1 Attacking the queen which has only one square to
go to as Ra8 is a mate.} Qb7 21. Rh2 {$1 There is no stopping the mate on
a2! And the queen on b7 is the main reason why this entire thing works.}
Ka6 22. Ra2# 1-0
[/pgn]

Sting-SF 7 finds the solution in 20 to 30 sec :

Code: Select all

FEN: q7/7R/k7/1p6/1p6/1P2B3/7K/8 w - - 0 1

Sting-sf-7-x64:
...
 44	00:29	 383 996k	12 909k	 0,00	1.Bd4 Qb8+ 2.Kh1 Qa8+ 3.Kg1 Qg8+ 4.Rg7 Qa8 5.Be3 Qb8 6.Bc5 Qa8 7.Rd7 Qg8+ 8.Kf1 Qb8 9.Kg2 Qg8+ 10.Kf1
 45+	00:30	 402 134k	13 031k	+0,08	1.Bd4
 45+	00:30	 402 151k	13 030k	+0,16	1.Bd4
 45+	00:31	 407 159k	13 023k	+13,77	1.Bd4
 45	00:32	 419 890k	13 021k	+12,52	1.Bd4 Qb8+ 2.Kh1 Qa8+ 3.Kg1 Qg8+ 4.Rg7 Qa8 5.Kf2 Qb8 6.Kf3 Qf8+ 7.Ke4 Qa8+ 8.Ke3 Qb8 9.Kd3 Qa8 10.Rf7 Qb8 11.Kc2 Qh2+ 12.Kb1 Qh1+ 13.Ka2 Qg2+ 14.Bf2 Qa8 15.Rg7 Qb8 16.Bg1 Qa8 17.Bd4 Qb8 18.Rf7 Qh2+ 19.Kb1
 46+	00:32	 420 989k	13 020k	+12,64	1.Bd4
 46+	00:32	 421 070k	13 018k	+12,76	1.Bd4
 46+	00:34	 449 832k	13 086k	+47,98	1.Bd4
 46	00:35	 459 170k	13 100k	+14,86	1.Bd4 Qb8+ 2.Kh1 Qa8+ 3.Kg1 Qg8+ 4.Rg7 Qa8 5.Kf2 Qb8 6.Ke3 Qe8+ 7.Kd3 Qa8 8.Rf7 Qb8 9.Kc2 Qh2+ 10.Bf2 Qb8 11.Kb1 Qa8 12.Ka2 Qb8 13.Rh7 Qa8 14.Kb2 Qb8 15.Bd4 Qa8 16.Ka1 Qb8 17.Rh6+ Ka5 18.Rh8 Qxh8 19.Bxh8 Kb6 20.Kb2 Kc6 21.Kc2 Kd5 22.Kd3 Ke6 23.Ke4 Kf7 24.Be5 Ke7 25.Kd5 Kd7 26.Bf4 Ke8 27.Ke4 Kf7 28.Kd4 Kg6 29.Kc5 Kf5 30.Bd6 Ke6 31.Kxb4 Kd7 32.Kxb5 Ke6 33.b4 Kd7 34.Ka6 Ke6 35.b5 Kf7 36.b6 Kg8 37.b7
 47+	00:35	 459 523k	13 096k	+14,98	1.Bd4
 47+	00:35	 459 656k	13 094k	+15,11	1.Bd4
 47+	00:35	 460 274k	13 075k	+61,43	1.Bd4
 47	00:35	 465 035k	13 058k	+77,08	1.Bd4 Qb8+ 2.Kh1 Qa8+ 3.Kg1 Qg8+ 4.Rg7 Qa8 5.Kf2 Qb8 6.Ke3 Qa8 7.Kd2 Qb8 8.Kd3 Qa8 9.Rf7 Qb8 10.Kc2 Qh2+ 11.Bf2 Qb8 12.Kb1 Qa8 13.Ka2 Qb8 14.Rh7 Qa8 15.Kb2 Qb8 16.Bd4 Qa8 17.Ka1 Qb8 18.Rh6+ Ka5 19.Rh8 Qxh8 20.Bxh8 Kb6 21.Kb2 

5)
Zugzwang too : 1B1k4/3p4/1Kp5/PpP2p2/1PqP1P2/8/1P6/8 w - - bm a6;
[pgn]
[Event "?"]
[Site "?"]
[White "w"]
[Black "b"]
[Result "*"]
[SetUp "1"]
[FEN "1B1k4/3p4/1Kp5/PpP2p2/1PqP1P2/8/1P6/8 w - - 0 1"]

1. a6 Kc8 2. a7 Qa2 3. Bd6 Qa4 4. Be7 Qa2 5. Bh4 Qa4 6. b3 Qa3 7. Be1 Qa2
8. Bd2 Qa1 9. Bc1 Qa2 10. Bb2 *
[/pgn]

6)
Stalemate theme, finds a draw score :
[pgn]
[Event "2.p ts70#1017 {v}"]
[Site "?"]
[Date "1966.??.??"]
[Round "?"]
[White "Van_den_Ende, J."]
[Black "[=0113.45e1f7]"]
[Result "1/2-1/2"]
[SetUp "1"]
[FEN "8/2B2k2/6p1/5P1p/6p1/p1p3PP/6P1/1n2K2R w K - 0 1"]
[PlyCount "14"]
[EventDate "1966.??.??"]
[Source "ChessBase"]
[SourceDate "2000.10.30"]

1. fxg6+ (1. Be5 $2 a2 2. Bxc3 Nxc3 3. O-O Nb1 4. fxg6+ Kg8 $1) 1... Kxg6 (1...
Kg8 2. O-O a2 3. Bf4 $1 (3. Be5 $2 a1=Q 4. g7 Qa3) 3... a1=Q 4. Bh6 Qa3 (4...
Qa7+ 5. Kh2 Qb8 6. g7) 5. g7) 2. Be5 (2. Ba5 $2 c2 $1) 2... a2 3. Bxc3 $1 Nxc3
4. O-O Nb1 (4... gxh3 5. Ra1) 5. h4 $1 a1=Q 6. Kh2 Qa2 7. Rxb1 Qxb1 1/2-1/2
[/pgn]

7)
Mate with the knight after some zugzwang
[pgn]
[Event "-"]
[Site "-"]
[White "w"]
[Black "b"]
[FEN "8/3ppp1p/3P4/4N3/8/3n1pKp/8/7k w - - 0 1"]
[SetUp "1"]

1. Nxd3!! exd6 { The Knight has to fight against 6 pawns. } 2. Kf2! { The only move. #25. } 2... d5 3. Ne1 d4 4. Nxf3 d3 5. Kf1 { Black can only move pawns. After that, it will be checkmated. } 5... h6 6. Kf2 h5 7. Kf1 h4 8. Kf2 f6 9. Kf1 f5 10. Kf2 f4 11. Kf1 d5 12. Kf2 d4 13. Kf1 d2 14. Nxd2 Kh2 15. Kf2 d3 16. Nf3+ Kh1 17. Kf1 d2 18. Nxd2 f3 19. Kf2 Kh2 20. Nxf3+ Kh1 21. Nd2 Kh2 22. Nf1+ Kh1 23. Ne3 Kh2 24. Ng4+ Kh1 25. Kf1 h2 26. Nf2# { Good job. }
[/pgn]

8)
Let's block the black king than bring the white king :
[pgn]
[Event "-"]
[Site "-"]
[White "w"]
[Black "b"]
[Result "1-0"]
[FEN "r1b4r/p4pk1/P3p1p1/1pBpPnPp/2pP1K2/2P3P1/4BP2/R6R w - - 0 65"]

65. g4 hxg4 66. Bxg4 Rxh1 67. Rxh1 Bd7 68. Bxf5 gxf5 69. Be7 Rg8 70. Ra1
Bc6 71. Ke3 Ra8 72. f4 Rg8 73. Kd2 Bd7 74. Kc2 Bc8 75. Rh1 Bd7 76. Kc1 Bc8
77. Kb2 Bd7 78. Ka3 Bc8 79. Kb4 Bd7 80. Kc5 Be8 81. Rh6 b4 82. Kxb4 1-0
[/pgn]

9)
Black is winning after 1...Bxh4! : 8/p7/5k2/pPp1p3/2P3Kb/8/8/3B4 w - - 0 2
[pgn]
[Event "Really hard and impossible puzzles: Solution to #4"]
[Site "https://lichess.org/study/S2ICwxRf"]
[Date "2016.07.21"]
[Variant "Standard"]
[ECO "?"]
[Opening "?"]
[FEN "8/p7/5k2/pPp1p3/2P3KP/8/8/3Bb3 b - - 0 1"]
[SetUp "1"]

1... Bxh4!! 2. Kxh4 Kf5 3. Kg3 Ke4 4. Kf2 Kd3 5. Ke1 Kxc4 6. Kd2 Kb4 7. Kc2 e4 8. Bg4 a4 9. Bf5 e3 10. Be6 c4 { and black wins, because white is not able to stop all the black pawns. }
[/pgn]

10)
Draw combination by stalemate :
[pgn]
[Event "-"]
[Site "-"]
[White "w"]
[Black "b"]
[Result "*"]
[SetUp "1"]
[FEN "q7/8/2p5/B2p2pp/5pp1/2N3k1/6P1/7K w - - 0 1"]

1. Ne4+ Kh4 2. Ng3 fxg3 3. Bb6 Qa1+ 4. Bg1 *
[/pgn]

11)
Rxf5!
[d] 4rb2/1p1q1ppk/p1n1p2p/2p1Pn2/3PNR2/2P2K2/P2QBP2/6R1 w - - bm Rxf5;

12)
White is winning after 1. Bxh7+! Kxh7 2. Ng5+! Kg8 3. Qe2! g6 4. Rh3!
[d]r1b2rk1/2q1bppp/pp2p3/2npP3/1n3P1P/2NBBN2/PPPQ2P1/1K1R3R w - - bm Bxh7;

13)
2 possible winning moves here : Qxd2! or Ng4!, hard for Stockfish.
[d]r4rk1/pb3pp1/1p1qpR2/2ppN3/3P4/2P4P/PP1pQ1P1/3R2K1 w - - 0 19

[Nordlandia]

• Stockfish 160526b Tactical
  
  Size: 1.22 MB
  
  http://www20.zippyshare.com/v/MUKeiSuG/file.html
  
  Source: http://immortalchess.net/forum/showthre ... post701589
  
  https://github.com/tthsqe12/asm/tree/master/Windows - updated ~ 8 hours ago.

[pgn][Event "5.c Farago MT Revista de Romana de Sah "]
[Site "?"]
[Date "1971.??.??"]
[Round "?"]
[White "Ruszczynski=P"]
[Black "(=0323.11e1d4)"]
[Result "1/2-1/2"]
[SetUp "1"]
[FEN "8/4B3/4p3/8/2rk1P2/2n5/2B5/4K3 w - - 0 1"]
[PlyCount "19"]
[EventDate "1971.??.??"]

{Revista de Romana de Sah/11 1973 EG#02122 @3: Ulrichsen=J EG=175 1/2009} 1. f5
Nd5 2. Bb3 Rc7 3. Bxd5 exf5 $1 (3... exd5 4. f6 Ke5 (4... Ke3 5. Kd1) 5. f7) 4.
Bd8 (4. Bd6 $2 Rd7 5. Be6 Rxd6 6. Bxf5 Ke3 7. Bh3 Rh6 8. Bg2 Ra6 $1) 4... Rd7
5. Be6 Rxd8 6. Bxf5 Ke3 $1 7. Bh3 $1 Rh8 (7... Rd2 $1 {<cook JU>}) 8. Bg2 Rd8
9. Bh3 Rh8 10. Bg2 1/2-1/2

[/pgn]

Code: Select all

[Event "5.c Farago MT Revista de Romana de Sah "]
[Site "?"]
[Date "1971.??.??"]
[Round "?"]
[White "Ruszczynski=P"]
[Black "(=0323.11e1d4)"]
[Result "1/2-1/2"]
[SetUp "1"]
[FEN "8/4B3/4p3/8/2rk1P2/2n5/2B5/4K3 w - - 0 1"]
[PlyCount "19"]
[EventDate "1971.??.??"]

{Revista de Romana de Sah/11 1973 EG#02122 @3: Ulrichsen=J EG=175 1/2009} 1. f5
Nd5 2. Bb3 Rc7 3. Bxd5 exf5 $1 (3... exd5 4. f6 Ke5 (4... Ke3 5. Kd1) 5. f7) 4.
Bd8 (4. Bd6 $2 Rd7 5. Be6 Rxd6 6. Bxf5 Ke3 7. Bh3 Rh6 8. Bg2 Ra6 $1) 4... Rd7
5. Be6 Rxd8 6. Bxf5 Ke3 $1 7. Bh3 $1 Rh8 (7... Rd2 $1 {<cook JU>}) 8. Bg2 Rd8
9. Bh3 Rh8 10. Bg2 1/2-1/2

[pgn][Event "3.hm New Statesman {and Nation}#82 @3"]
[Site "?"]
[Date "1973.??.??"]
[Round "?"]
[White "Kovalenko=V"]
[Black "(+0170.11g8d3)"]
[Result "1-0"]
[SetUp "1"]
[FEN "6K1/4p3/3b4/8/b7/2Bk4/7P/2R5 w - - 0 1"]
[PlyCount "17"]
[EventDate "1973.??.??"]

{EG#02248 @3: Veitch=W EG=41 7/1975} 1. h4 Bb3+ (1... Ba3 2. Ra1 Bb3+ 3. Kg7
Kxc3 4. Rxa3 e5 5. h5 Kb2 6. Rxb3+ Kxb3 7. h6 e4 8. h7 e3 9. h8=Q) (1... Bf4 $1
{<cook WV>} 2. Rf1 e5) 2. Kg7 (2. Kf8 $2 e5+ 3. Kg7 Ba3 4. Ra1 Kxc3 5. Rxa3 e4
6. h5 e3 7. h6 e2 8. Ra1 Bc2) (2. Kh8 $2 Ba3 3. Ra1 Kxc3 4. Rxa3 e5 5. h5 (5.
Ra5 e4 6. Re5 Bc2 7. h5 Kd2 8. h6 e3) 5... e4 6. h6 e3 7. h7 e2 8. Ra1 Bc2 9.
Re1 Kd2) 2... Ba3 (2... Bf4 3. Rf1 Kxc3 4. Rxf4 Bc2 5. h5 e5 6. Rf3+ Kd2 (6...
Kd4 7. h6 Be4 8. Rg3 Bc2 9. Kf6 Bh7 10. Rg7) 7. h6 Be4 8. Rg3) 3. Ra1 Bd6 4.
Bb2 Kc2 5. Bd4 Kd3 6. Rb1 (6. Bf2 $2 Be5+) 6... Bc2 (6... Kxd4 7. Rxb3 e5 8.
Rb6 Bc7 (8... Kc5 9. Rb1 e4 10. h5 e3 11. Kg6 Bg3 (11... Bf8 12. Kf5 Kd4 13.
Kf4 Kd3 14. Kf3 Bh6 15. Rd1+) (11... Kd4 12. Rd1+ Ke5 13. h6) (11... Kc4 12.
Rc1+ Kb3 13. h6) 12. h6 e2 13. h7) 9. Rc6 Bb8 10. h5 e4 11. Re6 Be5+ 12. Rxe5
Kxe5 13. h6 e3 14. h7 e2 15. h8=Q e1=Q 16. Qe8+) 7. Rc1 (7. Rb2 $2 Ba4 8. Ra2
Bb3 9. Rb2 Ba4 10. Rg2 Bc6 11. Rg4 Bf3) 7... Ba3 (7... Kxd4 8. Rxc2 e5 9. Rd2+
Kc5 10. h5 e4 11. Kg6 e3 12. Rd1) 8. Ra1 Bd6 (8... Kxd4 9. Rxa3 e5 10. Kf6 e4
11. Kg5 e3 12. Kf4 e2 13. Re3) 9. Bb2 1-0

[/pgn]

Code: Select all

[Event "3.hm New Statesman {and Nation}#82 @3"]
[Site "?"]
[Date "1973.??.??"]
[Round "?"]
[White "Kovalenko=V"]
[Black "(+0170.11g8d3)"]
[Result "1-0"]
[SetUp "1"]
[FEN "6K1/4p3/3b4/8/b7/2Bk4/7P/2R5 w - - 0 1"]
[PlyCount "17"]
[EventDate "1973.??.??"]

{EG#02248 @3: Veitch=W EG=41 7/1975} 1. h4 Bb3+ (1... Ba3 2. Ra1 Bb3+ 3. Kg7
Kxc3 4. Rxa3 e5 5. h5 Kb2 6. Rxb3+ Kxb3 7. h6 e4 8. h7 e3 9. h8=Q) (1... Bf4 $1
{<cook WV>} 2. Rf1 e5) 2. Kg7 (2. Kf8 $2 e5+ 3. Kg7 Ba3 4. Ra1 Kxc3 5. Rxa3 e4
6. h5 e3 7. h6 e2 8. Ra1 Bc2) (2. Kh8 $2 Ba3 3. Ra1 Kxc3 4. Rxa3 e5 5. h5 (5.
Ra5 e4 6. Re5 Bc2 7. h5 Kd2 8. h6 e3) 5... e4 6. h6 e3 7. h7 e2 8. Ra1 Bc2 9.
Re1 Kd2) 2... Ba3 (2... Bf4 3. Rf1 Kxc3 4. Rxf4 Bc2 5. h5 e5 6. Rf3+ Kd2 (6...
Kd4 7. h6 Be4 8. Rg3 Bc2 9. Kf6 Bh7 10. Rg7) 7. h6 Be4 8. Rg3) 3. Ra1 Bd6 4.
Bb2 Kc2 5. Bd4 Kd3 6. Rb1 (6. Bf2 $2 Be5+) 6... Bc2 (6... Kxd4 7. Rxb3 e5 8.
Rb6 Bc7 (8... Kc5 9. Rb1 e4 10. h5 e3 11. Kg6 Bg3 (11... Bf8 12. Kf5 Kd4 13.
Kf4 Kd3 14. Kf3 Bh6 15. Rd1+) (11... Kd4 12. Rd1+ Ke5 13. h6) (11... Kc4 12.
Rc1+ Kb3 13. h6) 12. h6 e2 13. h7) 9. Rc6 Bb8 10. h5 e4 11. Re6 Be5+ 12. Rxe5
Kxe5 13. h6 e3 14. h7 e2 15. h8=Q e1=Q 16. Qe8+) 7. Rc1 (7. Rb2 $2 Ba4 8. Ra2
Bb3 9. Rb2 Ba4 10. Rg2 Bc6 11. Rg4 Bf3) 7... Ba3 (7... Kxd4 8. Rxc2 e5 9. Rd2+
Kc5 10. h5 e4 11. Kg6 e3 12. Rd1) 8. Ra1 Bd6 (8... Kxd4 9. Rxa3 e5 10. Kf6 e4
11. Kg5 e3 12. Kf4 e2 13. Re3) 9. Bb2 1-0

[peter]

5)
Zugzwang too : 1B1k4/3p4/1Kp5/PpP2p2/1PqP1P2/8/1P6/8 w - - bm a6;
[pgn]
[Event "?"]
[Site "?"]
[White "w"]
[Black "b"]
[Result "*"]
[SetUp "1"]
[FEN "1B1k4/3p4/1Kp5/PpP2p2/1PqP1P2/8/1P6/8 w - - 0 1"]

1. a6 Kc8 2. a7 Qa2 3. Bd6 Qa4 4. Be7 Qa2 5. Bh4 Qa4 6. b3 Qa3 7. Be1 Qa2
8. Bd2 Qa1 9. Bc1 Qa2 10. Bb2 *
[/pgn]

Very tricky!
Found it in YACPDB
http://www.yacpdb.org/#search/MUIxazQzc ... MS8xLzA=/1
with a slightly different line of solution from O.Bláthy, in which the longer way with one more black pawn- move is shown.
1. a6 Kc8 2. a7 Qa2 3. Bd6 Qa4 4. Be7 Qa2 5. Bh4 Qa4
6. b3 Qa3 7. Bg3 Qa2 8. Bf2 Qa1 9. Be1 Qa2 10. Bd2 Qa1
11. Bc1 d5 12. Be3
In this one (or in your line above by 9...d5 instead of Qa2), you can fool even engines with switched off or very little nullmove by default like komodo-NM-off or Sting for quite a while yet.
Even if the eval already remains a winning one, much to much shuffling still then.

[Vinvin]

5)
Zugzwang too : 1B1k4/3p4/1Kp5/PpP2p2/1PqP1P2/8/1P6/8 w - - bm a6;
[pgn]
[Event "?"]
[Site "?"]
[White "w"]
[Black "b"]
[Result "*"]
[SetUp "1"]
[FEN "1B1k4/3p4/1Kp5/PpP2p2/1PqP1P2/8/1P6/8 w - - 0 1"]

1. a6 Kc8 2. a7 Qa2 3. Bd6 Qa4 4. Be7 Qa2 5. Bh4 Qa4 6. b3 Qa3 7. Be1 Qa2
8. Bd2 Qa1 9. Bc1 Qa2 10. Bb2 *
[/pgn]

Very tricky!
Found it in YACPDB
http://www.yacpdb.org/#search/MUIxazQzc ... MS8xLzA=/1
with a slightly different line of solution from O.Bláthy, in which the longer way with one more black pawn- move is shown.
1. a6 Kc8 2. a7 Qa2 3. Bd6 Qa4 4. Be7 Qa2 5. Bh4 Qa4
6. b3 Qa3 7. Bg3 Qa2 8. Bf2 Qa1 9. Be1 Qa2 10. Bd2 Qa1
11. Bc1 d5 12. Be3
In this one (or in your line above by 9...d5 instead of Qa2), you can fool even engines with switched off or very little nullmove by default like komodo-NM-off or Sting for quite a while yet.
Even if the eval already remains a winning one, much to much shuffling still then.

Yes, I didn't chose the more exact line but the most showy way.
But the ideas still : when the queen goes on a2, the bishop has to go on d2.
Then, if Qa3 -> Bc3 , controlling a1, forces Qa2, then Bb2 prevents Qa1 and Qa3, so white wins !
And, if Qa1 -> Bc1 , controlling a3, forces Qa2, then Bb2 prevents Qa1 and Qa3, so white wins !

[peter]

[Yes, I didn't chose the more exact line but the most showy way.
But the ideas still : when the queen goes on a2, the bishop has to go on d2.
Then, if Qa3 -> Bc3 , controlling a1, forces Qa2, then Bb2 prevents Qa1 and Qa3, so white wins !
And, if Qa1 -> Bc1 , controlling a3, forces Qa2, then Bb2 prevents Qa1 and Qa3, so white wins !

Of course, but the most fun against the engines with the one more black pawn-move is to see them fail again and again to find the shortest triangle-maneuver of the white Bishop to get the black Queen in the right moment at the right square before starting the final cut-off. The minimum-example of Zugzwang, going triangle, normally with King, here with Bishop, still a weakness of all engines.

[MikeGL]

Thanks for this puzzle compilation.

I haven't checked with other engines but critter1.6 32bit seems to solve
one of these difficult puzzles in less than 10 seconds on my old machine.


[d] 4rb2/1p1q1ppk/p1n1p2p/2p1Pn2/3PNR2/2P2K2/P2QBP2/6R1 w - - bm Rxf5;


1.Rxf5
first run found it in 3 seconds.
second run 11 seconds.
third run in 5 seconds.

critter 1.6 32bit
OS 32bit, dual core, hash 256MB

[Dann Corbit]

What score did Critter give to the position?

[MikeGL]

What score did Critter give to the position?

I tried to run it again just to get a screen grab. Below are the two runs which i did just now.
I am sure it can be easily replicated by anyone with a copy of critter1.6

4th run (with screengrab):




5th run (with screengrab):

[Vinvin]

Thanks for this puzzle compilation.

I haven't checked with other engines but critter1.6 32bit seems to solve
one of these difficult puzzles in less than 10 seconds on my old machine.


[d] 4rb2/1p1q1ppk/p1n1p2p/2p1Pn2/3PNR2/2P2K2/P2QBP2/6R1 w - - bm Rxf5;


1.Rxf5
first run found it in 3 seconds.
second run 11 seconds.
third run in 5 seconds.

critter 1.6 32bit
OS 32bit, dual core, hash 256MB

Yes, a lot of engines solve this quickly, mainly Stockfish has trouble here.

[peter]

13)
2 possible winning moves here : Qxd2! or Ng4!, hard for Stockfish.
[d]r4rk1/pb3pp1/1p1qpR2/2ppN3/3P4/2P4P/PP1pQ1P1/3R2K1 w - - 0 19

Really not easy to say, which is better.
That's after some Forward- Backward of both lines in 2 MV and depth 38:

r4rk1/pb3pp1/1p1qpR2/2ppN3/3P4/2P4P/PP1pQ1P1/3R2K1 w - - 0 1

Analysis by Stockfish 240716 64 POPCNT:

1. +- (3.28): 1.Qxd2 Ba6 2.Ng4 Rfc8 3.Qg5 Kf8 4.Rf2 Rc7 5.Qg6 cxd4 6.cxd4 Rb8 7.Qh7 Ke8 8.Qxg7 Kd7 9.Rxf7+ Kc8 10.Nf6 Qd8 11.Rxc7+ Qxc7 12.Qg8+ Kb7 13.Qxe6 Rf8 14.Nxd5 Qf7 15.Qxf7+ Rxf7 16.Nc3 Kc7 17.g4 Kd6 18.Kg2 Bb7+ 19.d5 Bc8 20.Kg3 Rg7 21.Nb5+ Ke5 22.Rc1 a6 23.Rxc8 axb5 24.h4 Kxd5 25.h5

2. +- (2.27): 1.Ng4 Rfc8 2.Qxd2 Kf8 3.Rxf7+ Kxf7 4.Rf1+ Ke8 5.Qg5 Ba6 6.Qh5+ Kd7 7.Ne5+ Kc7 8.Rf7+ Kb8 9.Nd7+ Kc7 10.Nxc5+ Kc6 11.Nxa6 b5 12.Qe2 Kb6 13.Nc5 Rc7 14.Rxc7 Qxc7 15.Qxe6+ Qc6 16.Qf7 a5 17.Qxg7 Qc7 18.Qf6+ Qc6 19.Qe7 Qc7 20.Nd7+ Ka7 21.Qe6 Rd8 22.Nc5 Rd6 23.Qe5 b4 24.cxb4 axb4 25.g4 Rc6 26.Qe3 Qg7 27.Kg2 Rh6 28.a3 Rh7 29.axb4 Qf6 30.g5 Qf5 31.Qa3+ Kb8