evalboardchess.com

 2024-10-28   16:45 UTC

Chess-Problems

Here you can find a collection of my favorite chess-problems frequently used to test a chess-engine.

The solutions can be found at the end of the page.


#01   ( mate in 4 , White to move )


The following problem I have found around 1982 in a newspaper.

I remember having thought over it around 2 hours but wasn't able to find

the correct solution.

This problem is a nice example to test the tactical skill of a chess-computer

at lower searching-depth.

If a chess-program is working selective already near the root the correct solution

will be found only late or not at all.

This problem has another solution as well, but with more moves than 4.


White:   Kc1, Qe2, Nd3/e4

Black:   Ka1, Qh6, Rc8, Bf7/h8, Pa5/c7/e3/g6/h5


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#02  ( test hashing, White to move and winning )


This problem is a fine example to test hashing ( if available ).

Without having hash-tables available this problem is unsolvable.

With hash-tables the solution will be found usualy quite fast, the table need not be

extraordinary large, around 20000 entrys are already sufficient.


White:  Ka1, Pa4/d4/d5/f4

Black:  Ka7, Pa5/d6/f5


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#03 ( mate in 7, White to move )


This problem will usualy be solved even by older classical machines.

It will be solved very fast if there is available a kind of check-extension

or a form of one-reply-extension.


White:  Kg1, Qa5, Rd7/h7, Nc5/g7, Pf5/g2

Black:  Kb8, Qe2, Rb2/c8, Bg5, Ng8, Pa7/b7/c6/d5/e5/f6


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#04  ( White to move and winning )


This problem is a complicated one, even for more modern chess-programs.

Most classical programs are not able to find the correct solution.

In the beginning of this project ( back to 2013 ) I still had little hope that one of the

programs running on the evaluation-board will ever find the correct solution within acceptable time ( lets say within 1 hour ).

Today, the solution will be found in this time by all 3 boards where Crafty-X is running.


White:  Kh1, Dd1, Ra1/f1, Bd5, Nc3/d4, Pa4/b2/c2/e4/g2/h2

Black:  Kg8, Qb6, Ra8/f8, Bc8/e7, Nd7, Pa6/b7/d6/e3/f7/g7/h7



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#05  ( Critical testposition for engines, White to move )


The following position is artifical but legal.

White to move but this is in principle don't care.

The interesting question is:  Can the engine still handle this position

without crashing down ?

There is exceptional high tension in this position, this requires more stack

than usual and could result in a system-crash.

By far not all engines are able to start calculation.


White:  Kf1, Qe6, Rd4/e7, Bg3/g6, Ne4/f4, Pa4/b4/c4/d2/e2/f2/g4/h4

Black:  Kc7, Qe5, Rd6/f3, Bd5/f6,  Nd7/f5, Pa5/b5/c5/d3/e3/g5/h5


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#06 ( White to move and winning )


This position has happened in a testmatch between an older version

of Stockfish ( as White ) and Crafty-X.

Stockfish is well known for powerfull mating-attacks and I am using Stockfish

as opponent for tuning-purposes frequently.

Most classical programs will never consider the key-move and Crafty-x fails to find

this move as well in the actual version.

Obviously, the search needs to be extended here in a working way...


White: Kg1, Qd1, Ra1/f1, Bc1/e4, Nc3, Pa4/b2/d5/g2/g5/h2

Black: Kg8, Qd6, Ra8/f8, Bc8, Nb6/c7, Pa5/b7/c5/e5/f7/g7/h7



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Solutions:


#01       1. Nb4 ! ( axb4  2. Nf6  Bxf6  3. Qa6 Ba2  4. Qxf6 ## )


#02       1. Kb1 !  +-  ( Emanuel Lasker )


#03       1. Dc7 ! ( Rxc7, 2. Rd8  Rc8, 3. Nd7 Kc7

              4. Ne6 Kd6 5. Nb6 Rxd8 6. Rd7 Rxd7 . 7 Nc8 ## )


#04       1. Rxf7 ! ( Rxf7 2. Bxf7 Kxf7 3. Qh5 Kg8 4. Qe8 Bf8

              5. Nd5 Qxd4 6. Ne7 Kh8 7. Rf1 Qf6 8. Rxf6 gxf6 9. Kg1 +- )


              White will soon play Nf5, Nxd6 and a5 gaining the bishop on c8 ).

              Best reply by Black is 2. Kh8 but White is winning even in this case.


#06      1. Rf6 !! ( gxf6 2. Bxh7 ! +- )