In problem No. 4 for instance, it is evident that Black has to keep the two squares b8 and b4 guarded on which the Knight a6 threatens mate. Of course, Black can take the Bishop f5, relieving the mating threat but White can move the Bishop to some other square in the diagonal h3-c8. Still, Black would have the defense Q-f8. This suggests as White's first move B-c8, interrupting the line from f8 to b8.
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8 | | | | | | | | |
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7 | ^K | ^Kt| | | | | | |
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6 | ^Kt| ^P | #K | | | | | |
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5 | | #P | | #P | | ^B | | |
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4 | | #P | | | | #Q | | |
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3 | | ^P | | | | | | |
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2 | | | | | | | | |
|———————————————————-|
1 | | | | | | | | |
+———————————————————-+
a b c d e f g h
DIAGRAM 80.—Problem No. 4.
Mate In Two Moves
The only square for Black's Queen from which to guard both b4 and b8 is then d6; but there the Queen blocks a flight square of the King, freeing the Knight b7 and enabling the mate Kt-a5.
The most difficult problems, of course, are those in which no mate is threatened in the initial position and in which Black can apparently foil all attempts to build a mating net. An example is the following position which illustrates the so-called "Roman idea."
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8 | | | | | | | | |
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7 | | ^Kt| | | #B | | | |
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6 | | | | | | | | |
|———————————————————-|
5 | | ^B | | | | | | |
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4 | ^K | | | ^P | | | | |
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3 | | | #K | | ^P | | | |
|———————————————————-|
2 | | | | | | ^Q | | |
|———————————————————-|
1 | | | | | | | | |
+———————————————————-+
a b c d e f g h
DIAGRAM 81.—Problem No. 5.
Mate In Four Moves.
Black's King is stalemate so that any check with the Knight would settle him. However, Black's Bishop guards the squares c5 and d6 from which the Knight could threaten a mate, and if White makes a waiting move with the Queen in the second rank to force Black's Bishop from his defensive position, Black replies B-g5 and takes the Pawn e3 on the following move, relieving the stalemate. The same maneuver would foil White's attempt to checkmate by (1) Q- e2, (2) B-d3 and (3) Q-c2, and the position really does not betray any other mating possibility.