Clearing the square is the opposite element of blocking the square. In this case, our piece occupies the square that we need for the other piece’s operation, so we move the first piece away to clear the square.
Botvinnik has moved his bishop with a check, clearing the c4 square for his knight.
Unblocking the pawn is another form of tactical element Clearing. We can clear the way for a pawn in two different ways.
First way is deflection of the opponent’s piece in front of the pawn.
White is planning an attack on the kingside. He would like to open some lines by moving his f-pawn forward. But the f-pawn is blocked and the path must be cleared.
1.Re5 deflects the black pawn, clearing the way for the white f-pawn.
The other method of unblocking the pawn is to force the opponent’s piece to a square diagonal to a pawn, so that pawn can take that piece and thus clear its path.
Black is forced to take the queen thus clearing the way for the white pawn.
The final aspect of this tactical element is Clearing the line. In this case a bishop or a rook clears the line for stronger line piece – queen.
The bishop clears the line for a queen up to square g6.