the maintenance of a Pawn in the center--are a perfectly
sufficient guidance in all King's Pawn openings, as no particular
difficulty exists for any piece to be developed to a favorable
square. Even if Black tries to avoid the well-known openings
which result from the reply (1) ..., P-e5 by playing (1) ..., P-
e6 for instance, or (1) ..., P-c5;, or, in fact, any other of the
twenty possible first moves, White will find the right way to
mobilize his men if he strictly adheres to those two principles
and resists the temptation to institute an early attack. A few
examples will show how simple the application of the principle
is.

I. (1) P-e4 P-d5

This attacks White's Pawn and White has to decide whether to
protect, advance or exchange him. The advance P-e5 and the
protection P-f3 are out of question because these moves are Pawn
moves which do not contribute to the development and are,
therefore, to be classed as mere loss of time. The protection (2)
P-d3 is not sufficient either as Black, after exchanging on e4,
would hamper White's development by exchanging Queens so that
White would lose the right of castling. The protection (2) Kt-c3
cannot be recommended as Black could deprive White of his center-
Pawn and obtain one for himself by Pxe4, (3) Ktxe4; P-e5. For all
these reasons White cannot do better than exchanges on d5.

At first sight this might seem a violation of the principles, as
Pxd5 is a Pawn move which does not further the development of the
pieces while Black, in retaking the Pawn, develops his Queen.
However, as was already pointed out on several other occasions,