MESON only includes orthodox directmates in 2, 3, 4 and 5 moves with one intended solution.

MESON does not include:

  • Problems with more than one intended solution.
  • Problems with more than one position for solving, such as twins and zeropositions.
  • Problems where retroanalysis shows that it is Black to play.
  • Problems with more than the normal set of pieces, such as two white queens.

ANTICIPATIONS are identified by software, which is not run every day. As the output of these various routines can be large and needs manual inspection, there will probably always be anticipations in MESON that have not yet been identified. All exact position anticipations are clear anticipations. All other noted anticipations are defined as such in the opinion of the webmaster. Others may have different opinions.

Versions and Afters

When versions or afters (hereafter referred to as just 'versions') are noted, both they and the original problem (if known) are in MESON and are linked. The original problem has its original composer(s) and source noted where known. Where the version has a different composer or composers from the original, they are given with the version. Where they are not known, the original composer is given. Where the source of the version is known, it is given. Otherwise, the source of the original problem is given.

Where a version has a given composer or composers different from the composers of the original problem, neither they, nor the webmaster, claim that they had any hand in the composition of the original problem.

Developed and maintained by Brian Stephenson.
Implemented with HTML5, MySQL, Perl (with, inter alia, CGI::Simple, HTML::Template & XML::LibXML) & CSS/Javascript (jQuery, Bootstrap & DataTables).