WHAT SQUARES DID I JUST LEAVE BEHIND? Squares against which my opponent can make threats and are signficant, especially squares on which <LOOSE PIECES> reside.

1) Morozevich vs Gelfand MC WCC 2007: 24 c4-e6! f7xe6 leaves behind the g6-square, leaving the Black g6-queen <UNDEFENDED> and lined up with the White b1-queen, thus creating a <PIN> that is <REINFORCED> with 25 d1-c1, regaining the piece.

2) Magill vs notyetagm CCC 2007: d3-b3 leaves behind the d4-square, making the White d4-knight <LOOSE> and its White e3-bishop defender is on the only square where it can <DEFEND>, so ... f5-f4! <REMOVES THE GUARD> by <DOMINATION (DRIVING OFF)>.

EVERY MOVE CREATES WEAKNESS BY LEAVING SQUARES BEHIND. IT IS A TACTICAL ERROR IF THOSE WEAKENED SQUARE ARE SIGNFICANT (LOOSE PIECES) AND CAN BE EXPLOITED.