DR CHALLENGES SOLVED (together with problem which first answered the challenge) Some of these challenges seem facile now, but at the time did not appear so. No doubt, many of these can be improved aesthetically or quantitatively. (Spoiler warning: reading these gives the game away, in some cases.) (C0) Does a position exists which is illegal by virtue of Article 1.3? (#025) (C1) Major piece (earlier version of #011) (C2) Include en passant. (#018) (C3) Include castling as theme (#020) (C4) More than 1 minor piece (NDE's version of #006) (C5) Uncapture of a pawn (#019) (C6) Stalemate in diagram position (#012) (C9) Position with no check, which is illegal whichever player has the move (#040) (C10) Position with no check, where last move can be determined, without stating who moved last (#015) (C11) Draw of a different form to insufficient material or stalemate (#014) (C12) Uncapture by a pawn. (#018) (C13) Promotion, but not as key (#023) (C14) Symmetric position (#040) (C15) Sequence of more than one move leading to stalemate (#018) (C17) Uncapture of a generic piece, which might be a pawn (#018) (C18) Include castling as key (#020) (C20) Promotion as key (#031) (C21) Include en passant as key (#019) (C25) Promotion as key, with unique winning substitute (#034) (C26) Capturing promotion as key (i.e. identifying the captured piece) (#035) (C27) Capturing promotion as key, with unique winning substitute (#035)