Position validity

When the mate search is launched, Problemist automatically checks whether the position is correct. If the position is incorrect or doubtful, a message explaining the first error encountered by Problemist is displayed. Fatal errors that will prevent any searches are the following:

No black or white king

More than one black or white king

Pawns on promotion squares

Black king in an apparent chess position (if the "Actual Play" or "Try Play" option is active)

The position is too complicated.

However, the following errors will lead to a simple warning message but will not hamper the mate search:

More than 16 white or black pieces

More than 8 black or white pawns

Promotion pieces

More than one bishop of the same color on squares of the same color.

The "Modified position" message appears when the solution is displayed if the position has been modified since the last search.