The following example may serve as an illustration. Supposing White plays after
1. P-Q4 P-Q4 2. P-QB4
His aim is to tempt Black’s centre pawn away and to make his QB4 and K4 accessible for his own forces. Black might be justified in taking the pawn, if he really could hold the pawn thus gained. We shall show later on that this is not so, and that White can win it back easily and advantageously. Therefore Black is more likely to play 2. P-K3. Not 2. … Kt-KB3; for after 3. PxP, KtxP; 4. P-K4 would open White’s game and drive the Knight away at once, gaining a move. Supposing, however, Black plays 2. … B-B4; should White now think mechanically, “I will take his centre pawn and consequently have the better game,” his deduction would be wrong. For after exchanging his Bishop for the Knight, which otherwise would drive his Queen away, Black brings the latter into a dominating square in the centre.
Diag. 17
3. PxP BxKt 4. RxB QxP
Black’s Queen cannot easily be driven away from her commanding position, particularly as White must lose a move to save his QRP. Meanwhile Black gains time for concentrating his forces for an attack which wins the Queen’s Pawn.
5. P-QKt3 Kt-QB3 6. P-K3 Castles QR 7. Kt-B3 P-K4
and wins the QP, or
5. P-QR3 Kt-QB3 6. P-K3 Castles QR