Chess puzzle

Examples include deducing the last move played, the location of a missing piece, or whether a player has lost the right to castle.

Sometimes the objective is antithetical to normal chess, such as helping (or even compelling) the opponent to checkmate one's own king.

Chess problems are divided into orthodox and heterodox types, both covering a variety of genres.

Orthodox problems employ the standard rules of chess and involve positions that can legally arise from actual gameplay.

Despite their unusual stipulations, helpmates and selfmates are usually considered orthodox problems, as they use standard chess rules.

If 2.Rg1, 2...Bc5 sets up a battery targetting g1, where White can stop checkmate only by moving the c1-bishop to connect rooks.