In every chess game, the goal of both white and black is to checkmate the opponent. In orthodox chess problems, the game proceeds only according to one principle - White mates, and Black resists, trying to prevent this. However, there are problems that deviate from these rules. A checkmate is also declared, sometimes a stalemate, but often this is done without a fight, by joint efforts. In other cases, checkmate is given by black pieces, sometimes by force. In other cases, one of the sides makes a series of moves, while the other makes only the last move, and so on. However, there are always very interesting combinations that deserve attention.
