Challenge Question 2: Is it possible that a Bishop may be pinned diagonally so that it is entrapped and cannot move, or move and capture? Answer:
Yes. Look at the board diagrammed below with Black to move. White has just move Qa2.
Black’s Queen Bishop at e6 is pinned by White Queen, but if Black moves the Queen Bishop to an empty square on the diagonal with the pin (other than f7 adjacent to the King) or moves and captures White’s Queen, White simply captures Black’s Rook at e8 with White’s Rook from e1 with checkmate (Rxe8#). If Black moves the Queen Bishop to f7 adjacent to the Black King (perhaps not thinking too clearly) with an obvious purpose to try to defend and protect the Rook and Bishop, White again simply captures Black’s Rook at e8 with White’s Rook at e1 with checkmate (Rxe8#) because the Queen Bishop is still pinned and cannot move and capture White’s Rook at e8. If Black moves the Queen Bishop to f7 adjacent to the Black King, White also could play and mate in two by capturing the Queen Bishop at f7 with White’s Queen checking Black’s King (Qxf7+) because the Queen is protected by the White’s Rook at b7, forcing Black’s King to move to h7 with mate by any of the following moves: Rxe8#, Qxe8#, or Qxg7#. Black should have resigned before this position was even reached because of White’s overwhelming material advantage and positional superiority.