One way to respond to a novel tactical problem is with novel tactics. And the impetus for this kind of thinking is fairly clear: if your own artillery is the problem digging you into a hole, then find a way to use less of it.
The mature form of this tactical framework is often called “Hutier” tactics, after German general Oskar Emil von Hitier, though he was hardly the sole or even chief inventor of the method. In its mature form, the technique went thusly: instead of attacking with large waves of infantry which cleared each objective in sequential order, attacks ought to be proceeded by smaller units, carefully trained with the layout of the enemy positions. Those units, rather than having a very rigid plan of attack, would be given those general objectives and left to figure for themselves how to accomplish them (“mission tactics” or Auftragstaktik), giving them more freedom to make decisions based on local conditions and the ground.
These elite spearhead units, called Stoßtruppen or “Stormtroopers” were well equipped (in particular with a higher amount of automatic firearms and hand grenades, along with flamethrowers). Importantly, they were directed to bypass enemy strong-points and keep moving forward to meet their objectives. The idea here was that the follow-up waves of normal infantry could do the slow work of clearing out points where enemy resistance was strong, but the stormtroopers should aim to push as deeply as possible as rapidly as possible to disorient the defenders and rapidly envelop what defenses remained.
These sets of infantry tactics were in turn combined with the hurricane barrage, a style of artillery use which focused on much shorter but more intense artillery barrages, particularly associated with Colonel Georg “Breakthrough” Bruchmüller. Rather than attempting to pulverize defenses out of existence, the hurricane barrage was designed merely to force enemies into their dugouts and disorient the defenders; much of the fire was directed at longer ranges to disrupt roads and artillery in the enemy rear. The short barrage left the ground relatively more intact. Meanwhile, those elite infiltration units could be trained to follow the creeping barrage very closely (being instructed, for instance, to run into the shell explosions, since as the barrage advantages, no gun should ever strike the same spot twice; a fresh shell-hole was, in theory, safe). Attentive readers will recognize the basic foundations of the “move fast, disorient the enemy” methods of the “modern system” here.
So did infiltration tactics break the trench stalemate? No.
First, it is necessary to note that while infiltration tactics were perhaps most fully developed by the Germans, they were not unique to them. The French were experimenting with many of the same ideas at the same time. For instance, basic principles of infiltration were being published by the French General Headquarters as early as April, 1915. André Laffargue, a French infantry captain, actually published a pamphlet, which was fairly widely distributed in both the French and British armies by the end of 1915 and in the American army in 1916, on exactly this sort of method. In many cases, like at the Second Battle of Artois, these French tactics bore significant fruit with big advances, but ran into the problem that the gains were almost invariably lost in the face of German counter-attacks. The Russians, particularly under Aleksei Brusilov, also started using some of these techniques, although Brusilov was as much making a virtue of necessity as the Russians just didn’t have that much artillery or shells and had to make due with less and Russian commanders (including Brusilov!) seem to have only unevenly taken the lessons of his successes.
The problem here is speed: infiltration tactics could absolutely more efficiently overrun the front enemy lines and even potentially defeat multiple layers of a defense-in-depth. But after that was done and the shock of the initial push wore off, you were still facing the same calculus: the attacker’s reinforcements, shells, artillery and supplies had to cross broken ground to reach the new front lines, while the defender’s counter-attack could ride railways, move over undamaged roads and then through prepared communications trenches. In the race between leg infantry and trains, the trains always won. On the Eastern Front or against the Italians fighting under the Worst General In History at Caporetto (1917), the already badly weakened enemy might simply collapse, producing massive gains (but even at Caporetto, no breakthrough – shoving the enemy is not a breakthrough, to qualify as a breakthrough, you need to get to the “green fields beyond” that is open ground undefended by the enemy), but against a determined foe, as with the 1918 Spring Offensives, these tactics, absent any other factor, simply knocked big salients in the line. Salients which were, in the event, harder to defend and brought the Germans no closer to victory. Eventually – often quite rapidly – the front stabilized again and the deadlock reasserted itself. Restoring maneuver, the actual end-goal of these tactics, remained out of reach.
Bret Devereaux, “Collections: No Man’s Land, Part II: Breaking the Stalemate”, A Collection of Unmitigated Pedantry, 2021-09-24.