I've read countless anecdotes about how opposing trenches on the Western Front were at times less than 100 meters apart from one another. How was this achieved given the proximity to the enemy who was often in plain sight?
Hi There,
This question does come up quite a bit and there have been some excellent responses to this question.
This recent thread has some excellent comments from u/TheWellSpokenMan
I'd add that I would highly recommend reading Erwin Rommel's Infantry Attacks. Rommel was a junior officer at the front in the Vosges region while the front solidified.
From his account we can infer an organic and ad hoc process.
Rommel describes how following an attack, the seized position would be subject to intense bombardment by the enemy. The only way to hold onto the gained ground without incurring enormous casualties was to dig in. The enemy might counterattack and be forced to dig in themselves.
Rommel repeatedly hammers home the importance of immediately digging in, and as deeply as possible too, in order to minimize casualties in any attack. This, to the extent that he records the ease of digging in his choice of ground, in addition to the usual military advantages or disadvantages of territory.