The legitimate war, so to speak, in this region is a mountaineering war.
The typical position is roughly as follows. The Austrians occupy valley
A which opens northward; the Italians occupy valley B which opens
southward. The fight is for the crest between A and B. The side that
wins that crest gains the power of looking down into, firing into and
outflanking the positions of the enemy valley. In most cases it is the
Italians now who are pressing, and if the reader will examine a map of
the front and compare it with the official reports he will soon realise
that almost everywhere the Italians are up to the head of the southward
valleys and working over the crests so as to press down upon the
Austrian valleys. But in the Trentino the Austrians are still well over
the crest on the southward slopes. When I was in Italy they still held
Rovereto.

Now it cannot be said that under modern conditions mountains favour
either the offensive or the defensive. But they certainly make
operations far more deliberate than upon a level. An engineered road or
railway in an Alpine valley is the most vulnerable of things; its curves
and viaducts may be practically demolished by shell fire or swept by
shrapnel, although you hold the entire valley except for one vantage
point. All the mountains round about a valley must be won before that
valley is safe for the transport of an advance. But on the other hand a
surprise capture of some single mountain crest and the hoisting of one
gun into position there may block the retreat of guns and material
from a great series of positions. Mountain surfaces are extraordinarily
various and subtle. You may understand Picardy on a map, but mountain
warfare is three-dimensional. A struggle may go on for weeks or months
consisting of apparently separate and incidental skirmishes, and then
suddenly a whole valley organisation may crumble away in retreat
or disaster. Italy is gnawing into the Trentino day by day, and