The defense has a general advantage, as, owing to air observation,
concealment is difficult. At the same time, in spite of all that, owing
to the power of moving troops at night, which the Germans exercised in a
very large extent, there was a large margin for surprise, even in spite
of air observation, and of this the enemy took full advantage.
I should like to say one word here as to the difficulty which the allied
Generals were confronted with in this respect. Before the battle the
greatest German concentration was in front of our troops. That was no
proof that the full weight of the attack would fall on us. There was a
very large concentration opposite the French lines. There was a very
considerable concentration--I am referring now to the German
reserves--on the northern part of our line.
After the battle began, or immediately before the battle, the Germans by
night brought their divisions from the northern part to the point where
the attack took place. They also took several divisions from opposite
the French in the same way and brought them to our front. But it would
have been equally easy for them, while concentrating troops opposite our
front, to manoeuvre them in the same way opposite the French. I am only
referring to that in order to show how exceedingly difficult it is for
Generals on the defensive to decide exactly where, in their judgment,
the attack is coming and where they ought to concentrate their reserves.