Connect the rooks

The rooks are connected when they occupy the same rank or file and no piece stands between them. They do not have to be adjacent. They only need a clear straight path so that each rook protects the other along that line.

In the opening, this connection usually appears after several tasks are completed: bringing out knights and bishops with developing moves, castling early, and moving the queen off the back rank. Connecting the rooks is therefore a practical sign that many pieces have left their starting squares.

Connection improves coordination. One rook can support the other as it enters a central file, replace it after an exchange, or help defend the back rank. Connection alone does not decide where the rooks belong, however. They are often most useful on an open line, behind a pawn that can advance, or opposite a concrete target.

Moving the queen to an unsafe square merely to complete this principle is not worthwhile. Nor must every player wait for connected rooks before starting tactical action. The position may demand meeting a threat or using a lead in development before all coordination is complete.