Invisible Defender

It is a piece that defends another piece indirectly. Or another way to look at it is you can move your piece to a square that looks unprotected, however if your opponent decides to capture it you will either win material or checkmate. Thus the piece looks undefended but in reality there is an invisible defender. When attempting this tactic you must be sure to have a solid threat or plan. Putting a piece on a square because you hope your opponent will take it is not a good idea. You will be just setting yourself up for a bad fall. Invisible defenders enable your pieces to navigate onto seemingly undefended squares, carrying your attack into enemy territory and they can be utilized to drag your opponent's pieces onto "bad" squares or away from key squares.