3 | ^P | | ^P | | | ^P | ^P | | |---------------------------------------| 2 | #B | | | | | | | ^P | |---------------------------------------| 1 | | | | | | | ^K | | --------------------------------------- A B C D E F G H

Diag. 11

Here, too, there is a flaw in the simple calculation, because the defending units are not secure.  Beginners should devote special attention to this position, which is in practice of frequent occurrence.

It can be easily perceived that the Bishop cannot capture the pawn at B7 on account of P-QR3.  But to take with the Knight would also be an error, because Black would then keep chasing away the covering Bishop.

1.  P-Kt4; 2.  B-Q6, K-B3; 3.  Kt-K8, B-B2; and wins one of the pieces.

Finally, one more example, in which one of the defending pieces being pinned makes simple calculation impracticable.

In Diagram 12 it seems at first sight as if Black could play KtxP:  although White can pin the Knight with R-K1

---------------------------------------
8 | #R |    | #B |    | #K |    |    | #R |
|---------------------------------------|
7 | #P | #P |    |    |    | #Kt| #P | #P |
|---------------------------------------|
6 |    |    | #P | #Kt|    |    |    |    |
|---------------------------------------|
5 |    |    |    |    |    |    |    |    |
|---------------------------------------|
4 |    |    |    |    | ^P | ^Kt|    |    |
|---------------------------------------|
3 |    |    |    |    |    |    | ^B |    |
|---------------------------------------|
2 | ^P | ^P |    |    |    |    | ^P | ^P |
|---------------------------------------|
1 | ^R | ^Kt|    |    |    | ^R | ^K |    |
---------------------------------------
A    B    C    D    E    F    G    H

Diag. 12

and then attack it once more with his Knight, Black would appear to have sufficient protection available, with his Kt and B. White has no time to double Rooks, because if he does so, after his R-K2 Black would play the King away from his file and allow the Knight to escape.

But White can, by a simple sacrifice, bring the slumbering R at R1 into sudden action: 

1. ...  KtxP; 2 R-K1, B-B4; 3.  Kt-B3, Kt-Q3; 4.  RxKt, KtxR; 5.  R-K1, and White wins two pieces for his Rook.

These illustrations will be sufficient to give the beginner an understanding of economy of calculation in all kinds of combinations.  His power of combining will grow speedily on this basis, and thrive in the fire of practical experience.  Where an opponent is missing, the gap must be filled by reference to such books as treat of the science of combination and give examples taken from actual play.

CHAPTER III

GENERAL PRINCIPLES OF CHESS STRATEGY