..., R-g6, (8) B-h4, B-a5 or c5, (9) P-d4 and Q-d3 the game
probably ends in a draw as it is unlikely that White can realize
an advantage from the doubled Pawn which he is ahead.

To the beginner the lines of play discussed in connection with
Diagrams 47 and 48 will have appeared rather complicated. This
they are, indeed, even for the experienced player; but it is by
no means necessary to memorize any of the variations. The
important thing to realize is the fact that in a position where
both players have castled on the King's side, a dangerous
weakness is created if the g-Pawn is forced to move, and if
pressure can be brought to bear upon the two squares which
through the move of the g-Pawn have lost their protection;
moreover, that a method to create such a weakness is the pinning
of the hostile King's Knight and the advance of the Queen's
Knight in the center.

Another important point that the variations discussed will bring
out to the observant reader is the order in which the different
pieces take their turn in the battle. First come the minor
pieces, then the Queen and then the Rooks. This, of course, is
not a rule that has to be adhered to under all circumstances, but
in most games it is a good rule to follow. The reason is obvious.
The Rooks have no opportunity of making themselves useful until a
file has been opened, while the Queen often finds an occasion to
enter the battlefield on a diagonal. Only in such games can the
Rooks be made to work at a comparatively early stage of the game,
in which the players have not castled on the same sides of the
board. For then the advance of the Pawns in front of the Rooks
does not create weakness which endangers their own King.