Przepiorka - Prokes
- Knights can attack any piece without in turn being attacked.
- In queen's pawn openings, black's b knight works better at d7 than at c6. It leaves the c file open for the rook or the queen, it enforces the f6 knight so that if it gets taken, it'll be replaced by the d7 knight.
- Every pawn move loosens the defending structure.
- Every undefended square created by the pawn move is a weakness.