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

Diagram 33

In the position of Diagram 34 White institutes a mating attack by (1) P-f6.  The only move to protect the mate on g7 is P-g6.  It will then be White’s desire to enter with his Queen on h6 again threatening the checkmate on g7.  He will, therefore, play either Q-f4 or Q-g5.  Black has no other way to defend himself against White’s threat than by K-h8 followed by R-g8.  But after K-h8; Q-h6, R-g8 White plays R-f3 and Black is unable to prevent White from sacrificing his Queen on h7 and mating by R-h3.

If Black’s Queen were standing on c5 instead of b5 he could avert the mate by moving the Rook f8 and playing the Queen to f8 thereby protecting g7.

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

Diagram 34.

The mate with Rook and Knight demonstrated by the position of Diagram 28 is liable to occur in several variations of the play which might result from the following situation: 

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

Diagram 35.