To which of the following squares can the white king move?
While the king can usually only move one square at a time, in this case the king is free to castle (notated “0-0”), so the rook would also move to f1 in the same move. Of course, this is assuming the king and the king-side rook have not yet moved. The king also cannot move to a square occupied by a piece of the same color or jump over the queen on d1.