The SokEvo collection of Sokoban puzzles was generated by a program that used random numbers and a solving program to 'evolve' them, primarily using the least number of moves required to solve a puzzle as its fitness value.

The puzzles are sorted by the least number of moves required to solve them, which is a crude but objective way of ordering them from easiest to hardest. This table of solution sizes can be used as a rough guide to difficulty. The first few puzzles are easy but those toward the end are quite hard.

• Download a zip archive containing all 107 puzzles as individual '.xsb' files.
• Download a compressed tar archive containing all 107 puzzles as individual '.xsb' files.
• Download all 107 puzzles as a single text file.
• Download all 107 puzzles as a single '.sok' enhanced-format file.

The four files above are all version 3.03 (9 February 2003). There will not be any further additions to the SokEvo collection.

The SokHard collection of Sokoban puzzles was generated by a program that used random numbers and Brian Damgaard's YASGen program to rapidly 'evolve' them, using the least number of pushes required to solve a puzzle as its fitness value. Almost all of these puzzles feature a single goal area (a target area).

The puzzles are sorted in release/creation order. This table of scores can be used as a rough guide to difficulty. The SokHard set is not intended for beginners – some puzzles are slightly difficult, yet others are very complicated.

• Download a zip archive containing all 163 puzzles as individual '.xsb' files.
• Download a compressed tar archive containing all 163 puzzles as individual '.xsb' files.
• Download all 163 puzzles as a single text file.
• Download all 163 puzzles as a single '.sok' enhanced-format file.

The four files above are all version 1.23 (22 March 2008). New entries appear at the end of a file and are prefixed by the version number in an archive. New versions are announced in the Yahoo! Sokoban group.

Note: You can receive messages from the Yahoo! group without the need for a Yahoo! ID – just use your existing e-mail account.
Please refer to this Yahoo! help page.

You may also find my graphical interpretation of the SokHard search trees entertaining (2.8 MB).

If you'd like to play these and other puzzles using your web browser, try my SokME game program, written using Sun's Java language.

• Play the SokEvo collection.
• Play the SokHard collection.

• Play the Multiban collection taken from Alfred Pfeiffer's Multiban homepage.
• Play the Hexoban collection taken from David W Skinner's Hexoban homepage.

To play these puzzles you will need to use a Sokoban game program – if you don't already have one, try this Google directory search.

• Brian Damgaard's Sokoban YASC (for MS Windows) has my puzzles built into it.
• For a more exhaustive set of Sokoban links visit the SokoSave homepage.

Each puzzle has been assigned a name at random, but where puzzles share the same surname they are from the same 'family' and may have similar features. No resemblance to actual persons, living or dead, is intended.

The puzzles in the SokEvo and SokHard collections may be freely distributed (which includes copying to other websites) and may be used commercially provided that they remain unchanged and I am credited with my name – Lee J Haywood. The titles of the collections and puzzles must not be amended. Any similarity to anyone else's work is entirely coincidental and unintentional.

Sokoban (倉庫番)™ is © Falcon Co., Ltd.