Tuesday, 31 July 2018

An example of a Syzygy Endgame Explorer search


White wins

The only move to win is 1. Qh1!!
This position was found with the help of SEE using the following commands:

[Tablebase "KQPkrr"]
[Output "out.pgn"]

[Position "1"]
[Eval "win"]
[SideToMove "white"]
[Piece2 "a8"]
[Piece5 "rank1"]
[Piece6 "fileH"]
[OnlyMove "yes"]
[Move "Qa8h1"]
[Capture "no"]
[Check "no"]

[Position "2"]
[AttackedByBlack "h1"]
[NotAttackedByWhite "h1"]

I was searching for a position where the only winning move for white is Qa8-h1, a silent move without capture or check. Two black rooks should protect h1, so the queen move should be a sacrifice on a double protected corner square! It turned out that I was lucky: there exists a position like that!
I have succeeded to turn this position into a nice study which will be published soon.

Friday, 13 July 2018

A tempo move which mirrors the position

Sometimes you wish you could pass the move to your opponent without making the slightest change in the position. Of course, the chess rules forbid this. But in the following position discovered with the help of SEE, you can "break" the rules!


White wins

1. Kf4! (zugzwang) (1. Nbc5? Nb6! =; 1. Nbd6? Nc7! =) 1... Nb6 2. Nbd6 +- (zugzwang) 1... Nc7 2. Nbc5 +- (zugzwang)

After the key we had practically the same position as before but with black to move!

Here are the other positions discovered so far:




The following positions feature more exotic material:



SEE also confirms my suspicion that the only position with similar properties having fewer than 7 pieces is one discovered by me last year:


White wins

1. Bh4! +- (zugzwang)

Friday, 15 June 2018

Syzygy Endgame Explorer (SEE)

Syzygy Endgame Explorer (SEE) is a software written by me for mining the newly generated 7-man endgame tablebases. In my previous post, I've presented the first study based on this mutual zugzwang found by SEE:

The tool can not only find mutual zugzwangs but can also identify positions where interesting moves are the only winning ones (like when a piece moves to a corner square or it is sacrificed). The software is still in the very early phases of development but my goal is to write a tool similar to CQL which searches tablebases instead of pgn files.

For example, this is a position found by SEE:

The only winning move for white is a surprising move to the corner square: 1.Ka1! (tempo). Black is in zugzwang, although not a mutual one. White could reverse its key by moving back to b2.

Making a full search in the tablebase is very time-consuming. Instead, I did searches by adding some constraints to the position of pieces. The following mutual zugzwang was found by restricting the knights to the long diagonal. It is interesting to see how two knights are immobilised in opposite corners:

The next position is a mutual zugzwang unless black has still kept the right to castle! If black can still castle, it saves the draw by 1...0-0! This position was found by restricting the black king to e8 and the black rook to h8.

An interesting mutual zugzwang:

There are 13 mutual zugzwangs with the same configuration of pieces in the upper left corner (with the same material):

rQ6/P2k4/8/8/8/5q2/4R3/3K4 w - - 0 1
rQ6/P7/8/8/R7/2q4k/8/3K4 w - - 0 1
rQ6/P7/8/q7/1R6/8/8/k3K3 w - - 0 1
rQ6/P2k4/5q2/4R3/8/8/1K6/8 w - - 0 1
rQ6/P2k4/8/4R3/8/5q2/2K5/8 w - - 0 1
rQ6/P2k4/2q5/4R3/8/1K6/8/8 w - - 0 1
rQ6/P7/8/3q4/R7/4K2k/8/8 w - - 0 1
rQ6/P4R2/8/8/4K3/8/6k1/7q w - - 0 1
rQ6/P7/4R1K1/8/6k1/8/6q1/8 w - - 0 1
rQ6/P7/4R2K/8/8/5q1k/8/8 w - - 0 1
rQ6/P3K3/2q5/4R3/k7/8/8/8 w - - 0 1
rQ6/P3K3/2q5/4R3/2k5/8/8/8 w - - 0 1
rQ6/P2k2K1/8/3q4/6R1/8/8/8 w - - 0 1

My underpromotion code also seems to work. A sample position:

1. c8=R!! 1. c8=Q? Ra2+! 2. Kxa2 Qxb3+ 3. Ka1 Qc3+! 4. Qxc3 stalemate 1... Rxc8 1... Ra2+ 2. Kxa2 Qxb3+ 3. Ka1 Qc3+ 4. Rxc3 +- 2. Qa6+ Kxb3 3. Qa2+ +-

Study 151

Árpád Rusz
Internet (RCS blog)
2018

White wins

The stipulation seems wrong: shouldn't white only fight for a draw?
1. Ba5+ Kc8 1... Kd7 2. Nf6+ +- 2. Nc5! 2. Nf6? Qg7 3. Bf3 Qc7! 4. Bg4+ Kd8 = 2... Qg7 3. Bf3! Thematic try: 3. Be4? Qf7 4. Bg2 Qh7 5. Bf3 Qg7 mutual zugzwang 6. Be4 Qf7 positional draw


mutual zugzwang

Now the black queen cannot move: it has to keep an eye on both the b7 and g4 squares (Focal Theme). The knight moves lead also to a disaster:

a. 3... Nf7 4. Bb7#
b. 3... Ng6 4. Bg4+ +-

Watch this study on a dynamic board! Click here!

This study features one of the first mutual zugzwangs found by Syzygy Endgame Explorer (SEE). More details in the next post.

Friday, 1 June 2018

Study 150

Árpád Rusz
Jirtdan Ty
2018
Special Commendation

White wins

1. d4 Nf3 1... Ne2 2. d5 Nc3 3. d6! Nxa4 4. d7 +- 2. d5 Ne5 2... Nd4 3. Kf6 +- 3. d6 3. Ke6? Nc4 = 3... Kg5 In order to win, white has to reach the same position but with black to move.


cyclic zugzwang - WTM

4. Ke6 Nd3 5. Bb5 5. d7? Nc5+ =; 5. Bc2? Nc5+ 6. Kd5 Nd7 = 5... Nf4+ 6. Kf7! Thematic try: It is too early for 6. Kd7?! (Position X') 6... Ng6 7. Bd3? Ne5+ 8. Ke6 Nxd3 9. d7 Nc5+ = 6... Ng6 7. Ba4! 7. d7? Ne5+ =; 7. Bc6? Ne5+ = 7... Ne5+ 7... Kf5 8. Bc2+ +- 8. Ke7! White has managed to transfer the move to black. While the white king made a triangle manoeuvre (Ke7-e6-f7-e7, 3 moves) and the bishop a switchback (Ba4-b5-a4, 2 moves), the black knight walked on a diamond-shaped path (Ne5-d3-f4-g6-e5, 4 moves). These manoeuvres result in a tempo loss by white.


cyclic zugzwang - BTM

8... Ng6+ 8... Kf4 9. Kf6! (9. Ke6? Nd3 positional draw 10. Kd5 Ne5 11. Ke6 Nd3 positional draw) 9... Ke4 10. Ke6 Nd3 11. Bc2 +- pin 9. Ke6 Nf4+

10. Kd7! (Position X) 10... Kf6 10... Ng6 11. Bc2 Ne5+ 12. Ke6 +- Now d3 is not available for the knight. Please, compare it with the thematic try. 11. Kc8! Nd5 12. Bb3! 12. d7? Nb6+ = 12... Ke5! 12... Ke6 13. d7+- pin 13. Kd7! Switchback 13... Nf6+ 14. Ke7 Kf5 15. Ba2(c4,f7) tempo 15... Ke5 16. Be6 +-

Watch this study on a dynamic board! Click here!

Related study: Study 73

Thursday, 17 May 2018

Study 149

Árpád Rusz
Problemist of Ukraine
2018

Draw

We have a symmetric initial position, so why shouldn't the only key move also be symmetric? It seems so natural to push the passed pawn... 1. d7? Kd1!! 1... Rc3? 2. Re8 Rd3+ 3. Kc6 =; 1... Re3? 2. Rc8 Rd3+ 3. Ke6 = 2. Rc8 2. Re8 Red2+ 3. Ke6 Rc6+ 4. Ke7 Rc7 -+ 2... Rcd2+ 3. Kc6 Re6+ 4. Kc7 Re7 -+

So the key should be a rook move. But where to place the rook?

Thematic try: 1. Rh8? Rc3 2. Rh4 Re8 3. Rd4+ Ke3 4. Rd1 Ke2 5. Rd4 Rd8 6. Ke6 Re3+ 7. Kf7 Rd7+ 8. Kf6 Now both black's king and one of its rooks are on the longer flank where there is more space to manoeuvre.

8... Re8 This is the quickest win. 9. Rd5 Re4 10. Kf5 Rh4! -+

The real key is a surprising move to the other corner:
1. Ra8!! After the rook was oddly placed in front of the passed pawn, now white seems to break another principle: "In rook endgames, it is usually better to choose the longer flank." 1... Re3 1... Rc3 2. Ra2+ = 2. Ra4! 2. d7? Rd3+ 3. Ke6 Rc6+ 4. Ke7 Rc7 -+ 2... Rc8 2... Rd3+ 3. Rd4 = 3. Rd4+ Kc3 4. Rd1! White has managed to transfer the rook behind its passed pawn! 4. d7? Rd8 -+ 4... Kc2 5. Rd4 Rd8 5... Kc3 6. Rd1 positional draw 6. Kc6 Rc3+ 7. Kb7 7. Kb6? Rb8+ -+ 7... Rd7+ 8. Kb6 Now both black's king and one of its rooks are on the shorter flank where there is less space to manoeuvre.

8... Rc8 9. Rd5 Rc4 10. Kb5 Now black doesn't have a move like 10. ..Rh4! from the thematic try! 10... Rc3 11. Kb6 Ra3! 12. Rd4! 12. Kc6? Rda7! 13. d7 R3a6+ 14. Kc5 Ra5+ 15. Kd4 Rxd5+ 16. Kxd5 Rxd7+ -+ 12... Kc3 13. Rd1 Kc4 14. Kc6 Rda7 15. Rc1+ Pushing the pawn would be fatal: 15. d7? R3a6# 15... Kb4 16. Rb1+ Ka5 16... Kc4 17. Rc1+ perpetual check 17. Rb5+ 17. d7? Rc3+ 18. Kd6 Rd3+ -+ 17... Ka6 17... Ka4 18. Rd5 = 18. Rb6+ Ka5 19. Rb5+ perpetual check

Watch this study on a dynamic board! Click here!

Monday, 14 May 2018

Study 148

Árpád Rusz
Variantim
2017

White wins

1. Ra8+!
a. 1... Rb8 2. Rc8+! 2. Rxb8+? Qxb8 3. Qxd7 Qf4+ 4. Kg6 Qg5+! 5. Kf7 Qh5+! 6. Kf8 Qh6+ = 2... Rd8 3. Qe8+!! Qf8+


Domino Theme

Now the pieces will start to fall one by one like some dominoes. Maybe this new theme should be called the "Domino Theme". 4. Qxf8+ Rxf8 5. Rxf8+ Rxf8 6. Rxf8#

b. 1... Rd8 2. Rxd8+ Qxd8 3. Qxb5 Qd2+ fork 3... Qf8+ 4. Kh5 +- 4. Kg6 Qg2+ The white rook was taboo. 5. Kf7! The pawn is also untouchable! 5. Kxf6? Qg7+ 6. Kf5 Qh7+ 7. Kg4 Qe4+ = 5... Qg8+ 6. Ke7! Qh7+ 7. Kd6! 7. Ke6? Qh3+ 8. Kd6 h1=Q 9. Qe8+ Kg7 (9... Kh7? 10. Qf7+ Kh8 11. Qxf6+ Kh7 12. Rc7+ +-) 10. Rc7+ Kh6 = 7... h1=Q 8. Qe8+ Kg7 9. Qd7+! 9. Rc7+? Kh6 10. Qe3+ Kg6 11. Qg3+ Kh6 = 9... Kh8 10. Qc8+! 10. Rc8+? Qg8 = 10... Kg7 11. Qg4+ Kf8 11... Kh6 12. Rxh1#; 11... Kh8 12. Rc8+ +- 12. Rc8+ Kf7 13. Rc7+ Kf8 14. Qc8#

Watch this study on a dynamic board! Click here!

Saturday, 12 May 2018

Polgar Starchess Endgame Studies

Invented by László Polgár, father of the famous Polgár sisters, Starchess is played on a star-shaped board with rules which are very similar to those from classical chess. This chess variant seems very suitable for endgame study composition.

-1-
Árpád Rusz
Internet
2009

Thematic try:

The end position is the following mutual zugzwang:

In the solution, the white king triangulates trying to reach the same position but with BTM. In order to find the correct first move, one has to see the final mutual zugzwang! These kind of long triangulations are very rare even in chess studies.

During solution, two dead white pawns are coming back to life. This theme is impossible in chess.

-2-
Árpád Rusz
Internet
2009

The white knight and the black king follow these paths during solution:

Black avoids two echo stalemates by echo promotions to bishop!

Tuesday, 8 May 2018

Study 147

Árpád Rusz
6th FIDE World Cup
2017
2nd Prize

White wins

Thematic try: 1. Nd3? Nf4! 2. Nc5+ 2. Nxf4+ Ke5 = 2... Kd6 3. Nd7 Ne6 4. e5+ Kd5 5. Kf7! Nc5 6. Ng4! Nxd7 7. e6 Nb6 8. Ne3+ 8. e7 Nc8 9. e8=Q Nd6+ = 8... Kc5 9. Ke7! Nc8+ 10. Kd7 Nb6+ 11. Kd8


Position X'

In this position, black has a saving manoeuvre! 11... Nc8! 12. Nc4! 12. Kxc8 Kd6 = 12... Na7!! Black uses the extra file on the longer flank! 12... Kd5? 13. Kd7 +- 13. Na5 13. e7 Nc6+ = 13... Nc8! 14. Nc4 Na7 15. Ne5 Nc8! 16. Nc4 Na7 positional draw

1. Nf3! Nd4! 1... Ng3 2. e5 Nf5 3. Nd3 Nd6+ 4. Kf8 +- 2. Ng5+ 2. Nxd4+? Ke5 = 2... Kf6 3. Nf7 Ne6 4. e5+ Kf5 5. Kd7! 5. Ke7? Ng5 6. Nc4 Nf3 = 5... Ng5 6. Nc4! 6.Nxg5? Kxe5 = 6... Nxf7 7. e6 Nh6 By sacrificing its h2 knight white had managed to keep the black knight on the shorter flank. 7... Kf6 8. e7 +- 8. Ne3+! 8. e7? Ng8 9. e8=Q Nf6+ = 8... Kg5 9. Ke7! Ng8+ 9... Kf4 10. Kf8! +- 10. Kf7 10. Kf8? Kf6! = 10... Nh6+ 11. Kf8 +-


Position X

In the thematic try we saw a mirrored position (Position X') but now black doesn't have a saving manoeuvre which starts with a knight sacrifice. There is no extra file next to the h-file!

Watch this study on a dynamic board! Click here!

Friday, 27 April 2018

Study 146

Árpád Rusz
Zinchuk-80 MT
2018
1st-2nd Prize

White wins

1. Rh2+ (1. c6? Ng3 2. c7 Rc4+ 3. Rc2 Ne2+ 4. Kd2 Nc3 =) 1... Kg3 2. Rd2! (2. Rxh1? Rc4+ =) 2... Rc4+! (2... Rxd2 3. Kxd2 Nf2 4. Bd5! (4. Bh1? Nxh1 5. c6 Nf2 6. c7 Ne4+ 7. Kd3 Nd6 =) 4... Ng4 5. c6 Nf6 6. c7 +-) 3. Rc2 Rxc2+ 4. Kxc2 Nf2 The knight has managed to escape from the corner square. Unfortunately, the g3 square was blocked by the king so the knight had to choose the inferior f2 square.

5. Bh1!! Umnov Theme. The bishop moves to a square just left by the knight. (5. Bd5? Ng4 6. c6 Ne3+ 7. Kb3 Nxd5 =; 5. c6? Ne4 6. c7 Nd6 =) 5... b3+! (5... Nxh1 6. c6 Nf2 7. c7 Ne4 8. c8=Q +-) 6. Kxb3 (6. Kb2? Nd3+ =; 6. Kb1? Nd1! 7. c6 Nc3+ 8. Kb2 Nb5 =) 6... Nd3 7. c6 Nc5+ 8. Kc4 Ne6 9. Kd5 Nc7+ 10. Kc5! (10. Kd6? Na8! 11. Kd7 Nb6+ 12. Kd6 (12. Kc7 Nc4 =) 12... Na8 positional draw) 10... Na8! Compared to the initial position, the knight and the bishop have interchanged their places.

11. Kb5 Kf4 12. Ka6 Ke5 (12... Nc7+ 13. Kb6 Ne8 14. Bd5 Ke5 15. Bf7 Nd6 16. c7! +-) 13. Kb7 Kd6

14. Kxa8 +- Who would have thought that the knight will be captured not on h1 but on the opposite corner square?

Watch this study on a dynamic board! Click here!

Related study: Study 122

Tuesday, 3 April 2018

Study 145

Árpád Rusz
Problem Paradise
2017

White wins

1. Bxf3! Rxg5! 1... Rxf3 2. g6 Rf1+ 3. Ka2 Rf8 4. g7 Ra8+ 5. Kb3! echo 5... Kd3 6. Kb4 Rb8+ 7. Ka5 Kc4 8. Be5 Re8 9. Kb6! +- (9. Bd6? Rg8 10. Bf8 Rxg7! 11. Bxg7 Kxc5 =) 2. c6 Ke3

3. Bh1! Rg1+ 4. Kc2!! echo 4. Ka2? Rxh1 5. c7 Rc1 =; 4. Kb2? Rxh1 5. c7 Rh8 = 4... Rxa1 4... Rxh1 5. c7 chameleon echo 5... Rh8 6. Bxh8 +- 5. c7 chameleon echo 5... Ra8 6. Bxa8 +-

Watch this study on a dynamic board! Click here!

Thursday, 18 January 2018

Study 144

Árpád Rusz
The Problemist
2018

Draw

1. Bxd7! 1. Nc5+? Kd5 2. Nxd7 Nxd6 3. Nf6+ Kc5! 4. Nd7+ Bxd7 5. Bxd7 Position X' 5... d3 -+ 1... Bxd7 2. Nc5+ The knight leaves the b3 square, but it will return there after a long trip. 2... Kd5 3. Nxd7 Nxd6 3... Kxd6 4. Nb6 d3 5. Nc4+ Kc5 6. Nd2 = 4. Nf6+! 4. Nb6+? Kc6 -+ 4... Ke6 4... Kc5 5. Nd7+ Position X - The knight proves to be more efficient than the bishop in the fight against the passed pawn. 5... Kd5 (5... Kc6 6. Ne5+ Kd5 7. Nd3 =) 6. Nf6+ Kc5 (6... Kc4 7. Ng4 d3 8. Ne5+ =) 7. Nd7+ perpetual check 5. Nh5! This extra file was missing from the other flank. 5... Kf5 5... d3 6. Nf4+ = 6. Ng3+ Kg4 7. Nf1! The knight has to stop the pawn before it reaches d2. 7. Ne2? d3 8. Nc3 d2 -+ 7... Kf3 8. Nd2+ Ke2 9. Nb3! = During the trip, the knight drew a big square on the board!

Watch this study on a dynamic board! Click here!

Tuesday, 16 January 2018

Study 143

Árpád Rusz
Joiţa MT
2018

White wins

The a4 pawn prevents a simple win (1.Rf4 followed by 2.Ra4#). In order to win, white will try to reach the same position but without the a4 pawn. But how does the "disappearing pawn magic trick" work?

1. Bf3! Logical try: 1. Rf4? Rd6! -+; 1. f3? Rf1! = 1... Rd4 1... Bxf3 2. Rxf3


Saavedra's double attack (echo)

2... Rh1 3. Ra3#; 1... Rd6 2. Rxd6 Bf5+ 3. Rd3! +- 2. Kc3! 2. Bxg4? Rxg4 3. Rxh6 Rg8 4. Ra6 Ra8 = 2... Rxa4 3. Kb3 Bd7! 3... Rd4 4. Bxg4 Rxg4 5. Rc6 Kb1 6. Rxc7 +- 4. Bc6! Rd4 4... Bxc6 5. Rxc6


Saavedra's double attack (echo)

5... Rxa5 6. Rc1# 5. Kc3! 5. Bxd7? Rxd7 6. Rxh6 Rd8 = 5... Rd1 6. Kc2 Bg4 We are back to the initial position but the a4 pawn has disappeared! 6... Rd4 7. Bxd7 Rxd7 8. Rf4! +-


The a4 pawn has disappeared!

7. Rf4! Rd6 8. Ra4#

Watch this study on a dynamic board! Click here!

Related study: Saavedra 1