Threats of this kind more frequently occur in connection with a discovered Check.  As an example the following opening will serve:  (1) P-e4, P-e5; (2) Kt-f3, Kt-f6; (3) Ktxe5, Ktxe4; (4) Q-e2, Kt-f6.  Black’s last move exposes his King to a discovered Check, and White wins the Queen by playing (5) Kt-c6+.

Next to the Knight the Queen is most frequently in a position to carry out a double attack.  Two typical examples are shown in the following diagrams.

After the opening moves (1) P-e4, P-e5; (2) P-f4, B-C5; (3) Pxe5?? the position of Diagram 23 is reached, in which Black wins a Rook by Q-h4+.  White cannot reply (4) K-e2 on account of Qxe4 mate.  His only move is (4) P-g3 and then follows Qxe4 attacking King and Rook simultaneously.

This opening offers another opportunity to demonstrate the dangerous mobility of the Queen.  Instead of (3) Pxe5 White should have played (3) Kt-f3.  The game could then have continued as follows:  P-d6; (4) B-c4, Kt-f6; (5) Pxe5, Pxe5:  Again White cannot win the Pawn e5 for (6) Ktxe5 would be answered by Q-d4, attacking Knight and Bishop and threatening mate on f2.

+---------------------------------------+
8 | #R | #Kt| #B | #Q | #K |    | #Kt| #R |
|---------------------------------------|
7 | #P | #P | #P | #P |    | #P | #P | #P |
|---------------------------------------|
6 |    |    |    |    |    |    |    |    |
|---------------------------------------|
5 |    |    | #B |    | ^P |    |    |    |
|---------------------------------------|
4 |    |    |    |    | ^P |    |    |    |
|---------------------------------------|
3 |    |    |    |    |    |    |    |    |
|---------------------------------------|
2 | ^P | ^P | ^P | ^P |    |    | ^P | ^P |
|---------------------------------------|
1 | ^R | ^Kt| ^B | ^Q | ^K | ^B | ^Kt| ^R |
+---------------------------------------+
a    b    c    d    e    f    g    h

Diagram 23.

Diagram 24 shows a typical case of a double threat with the Queen in conjunction with other pieces.  White on the move plays B-d3, and now Black cannot castle as White would continue with Q-e4 threatening mate through Qxh7 and at the same time attacking the Bishop e7 for the second time who is only once protected.  Black would have to defend the mate by either P-g6 or P-f5 or Q-h5 and White would capture the Bishop.

When castling on the King side a player must always beware of an attack by the Queen and another piece on the King’s Rook’s Pawn.

+---------------------------------------+
8 | #R |    | #B |    | #K |    |    | #R |
|---------------------------------------|
7 | #P | #P | #P | #P | #B | #P | #P | #P |
|---------------------------------------|
6 |    |    |    |    |    |    |    |    |
|---------------------------------------|
5 |    | ^B | #Q |    |    |    |    |    |
|---------------------------------------|
4 |    |    |    |    |    |    |    |    |
|---------------------------------------|