Considerations of this kind will help to improve our judgment in many of the various openings treated in the following pages.

We will class the openings in this way: 

A. White 1.  P-K4.

(a) Black 1.  P-K4
(b) Black 1.  Any other move

B. White 1.  P-Q4.

(a) Black 1.  P-Q4
(b) Black 1.  Any other move

C. White 1.  Any other move

We shall find that openings classed under C generally lead to positions treated under A and B.

A. We have already come to the conclusion that after 1.  P-K4, P-K4 White does well to try to force the exchange of Black’s centre pawn on Q4 or KB4, and that Black will try to counteract this, unless by allowing the exchange he gets a chance of exerting pressure in the centre by means of his pieces.

We will first see what happens when White undertakes the advance in question on his second move.  Superficially the difference between 2.  PQ4 and 2.  P-KB4 is that in the first case the pawn thus advanced is covered, while in the second it is not.  An opening in which a pawn sacrifice is offered, is called a “gambit”; 2.  P-KB4 is therefore a gambit.

2.  P-Q4 is only a gambit if after 2. ...  PxP White does not recapture the pawn.  Nevertheless this opening has been called the “centre gambit,” and though the denomination is not correct we will adhere to it, as it is in general use.

A very considerable difference between the centre gambit and the King’s gambit lies in the fact that in the former acceptance is compulsory, whilst in the second it may be declined.

For:  2.  P-Q4 threatens to take the King’s Pawn.  To defend it by means of 2. ...  P-Q3 is unwise, since White exchanges pawns and then Queens, by which Black loses his chance of castling and impedes the development of his Rooks. 2. ...  Kt-QB3 is also bad, since after 3.  PxP, KtxP; 4 P-KB4, White drives the Knight away, gaining a strong hold on the centre, and Black has no compensation for giving up his centre pawn.  It may be mentioned here that after 2. ...  Kt-QB3, 3.  P-Q5 would be a useless move, as to begin with it would be inconsequent, since P-Q4 was played in order to clear the centre, and moreover it would block up a diagonal which could be most useful to the King’s Bishop.

We conclude now that Black cannot hold his pawn at K4.  He must relinquish the centre by 2. ...  PxP.  He will now either attempt to bring away White’s King’s Pawn by advancing his own QP to Q4, or try to utilise the King’s file, which was opened by his second move, and operate against White’s KP.  The Rooks are indicated for this task.  We shall refer to the execution of these plans later on.

In the King’s gambit, White’s attempt to bring away Black’s King’s Pawn may be safely ignored.