When interpreting the instructions to a chess problem, is a piece automatically considered to "control" the square it's on, even if that square isn't threatened by any friendly piece, and an enemy piece could capture it with impunity?
I ask because of this recent puzzle that was posed on the Futility Closet site:
What’s the minimum number of bishops needed to control all the squares on a standard chessboard?
The answer they provide is:
a row of eight bishops across either of the board’s two middle ranks
But this answer seems to me to leave all the squares that the bishops themselves reside on completely uncontrolled, and that the correct answer should be two higher than the one provided.
Is my interpretation correct, or is this the standard usage of the word "control"?