File of FEN positions for hard positions and mate problems

[jshriver]

From time to time you see posts here with hard positions for mate-in-x to test engines. Anyone have or recommend a file with such positions in FEN format? If so would greatly appreciate a link.

Cheers!
-Josh

[peter]

From time to time you see posts here with hard positions for mate-in-x to test engines. Anyone have or recommend a file with such positions in FEN format? If so would greatly appreciate a link.

Maybe you already know

https://github.com/vondele/matetrack/bl ... etrack.epd

Chest.epd is included, the well known program from Franz Huber you get here, if you don't already know too:

https://fhub.jimdofree.com/

As for other "hard" puzzles, it's very much a matter of definition and purpose, test suites there are many, as one rather complete collection of composed studies Harold van der Hejiden- database still is the gold standard for me, but it's not in .epd- format and it's not free, regards

[Norm Pollock]

This might help. They are mate-in-x positions where x goes from 2 to 7. But they are "epd" files not "fen".

The white-to-move files and the black-to-move files are flipped versions of each other.

The pv opcode for each record contains a mating path of minimal length.

https://www.mediafire.com/file/uo3rgjpy ... 4A.7z/file

[chesskobra]

scid vs pc comes with 'mate in x' puzzles installed. After installation you find them in the bases directory. They are in the scid format, but you can export them to pgn, and extract FEN strings.

Also take a look at the following (but they are not 'mate in x' types).

https://github.com/Spill-The-Tea/Spillt ... _Testsuite - a large collection but not well documented, so you have to check what interests you; it seems the person stopped the project. From the collection you may get some test suites by Eigenman.

and https://www.chessprogramming.org/Test-Positions

and https://arasanchess.org/tests.shtml

and http://gorgonian.weebly.com/pgn.html more than 3500 combinations.