• Tanks

Highly overhyped. They were basically 40C inside at all times and guaranteed to break down. They could, on a flat surface, go a max speed of 5mph. In combat conditions and uneven terrain it would at best expect a maximum speed of 1.5-2mph. They were huge targets, were too slow and vulnerable to really be of use, and are extremely overhyped in the post-war narrative by looking at their WW2 manifestations rather than their WWI applications.

The availability rates for the battle of Amiens, 1918, tells its own story.

•August 8th, 1918: 414 available

•August 9th, 1918: 145 available

•August 10th, 1918: 85 available

•August 11th, 1918: 38 available

•August 12th, 1918: 6 available

• Planes

Generally reconnaissance and bombing. Though much smaller scale than we expect from their WW2 counterparts they still provided on the dot spotting for ground troops and further could harry the enemy forces via manually dropped bombs.

• Field Guns

Coordination with the infantry. They would be used quickly and rapidly rather than over weeks in bombardment. The hope was to quickly hit the enemy with everything you had, stop, and then hit them with your infantry while they were still reeling from the immediate shock of the barrage. Field guns would also 'box in' enemies disallowing retreat while also not allowing reinforcements to safely advance. Further uses would be things like Creeping Barrages where the artillery would advance in step with the infantry to constantly be hitting the enemy immediately prior to the infantry's attack on those positions.

• Grenades & Mortars

I combine these two since they both serve great functions. Lots of tossing meant 'grenade warfare' dominated the battlefield; especially in 1917 when we see a large surge of fighting taking place in shell craters and ditches in no mans land. Mortars also supplemented a similar purpose but on a platoon level: It allowed close range, on the spot, personal use of 'artillery' to strike weak points which the platoon or company could exploit.

But basically none of these came out of nowhere. Grenades were there since 1915, planes were since 1914, tanks were there since 1916 and personal mortars were around since 1915 as well. These were all tools which had, for the entirety of the war, helped facilitate taking trenches and they were damned effective at doing it. The issue wasn't taking trenches, taking a trench was actually incredibly easy. The issue was keeping the trench afterward. Enemy counterbattery could create a zone of denial for reinforcements to come up while their reserves hit you back; the Germans were especially keen on just giving up the first few trenches and then striking back in a counter-assault against an isolated enemy. Platoon level warfare had been used locally in 1916 and was universal doctrine in 1917 and yet we still had over a year of trench/crater warfare.

Really the issue here is just a misunderstanding. After 1915 the war was not a stalemate. The Somme was by no means a failure it crushed the Verdun offensive indirectly and also caused the Germans to completely give up on the Western Front. It caused the German withdrawal even after the territorial losses from the battle to the Hindenburg Line which exemplifies this. The issue was just that whenever you pushed somewhere it was very hard to push somewhere else at the same time so basically it would be a case of you throwing your men here and they would throw their men there and it's a struggle for that localized area. It's hoped after many years of this done in a responsible manner that the other side flat out won't be able to fight anymore and that's, ultimately, what changed.

Germany used revolutionary tactics, yes, in the Spring Offensives but the Russians used them in 1916 and the British were experimenting with them in 1917. Germany gained so much ground in the Spring Offensives because they threw caution to the wind and threw literally everything their had and concentrations of their most experienced, battle hardened men into some of the weakest points of the Allied line and just started making a bolt to Paris and in North to the sea to try and encircle the British. The reason the Hundred Days was so effective was because the Germans were crushed at that point: They lost all their experienced men in that last ditch offensive, their homefront was in open rebellion along with their entire surface navy and most of their home stationed army, Berlin was taken, the economy was in absolute shambles (90% of their ordinary budget was to paying off interest from war loans), everyone was starving, and they couldn't make any more bullets. They had no way they could fight back and the addition of a few million Americans only tacked onto this.

So it was less some random eureka moment of "Doh! We can NOT run into machine guns!" happened or whatever; the tools for the offensives in 1918 were in place well before 1918 and the doctrines used there were in development long before 1918 as well. The issue of the 1918 offensives and their successes is more suited for the strategic and operational level of war, not the tactical.

The war of 1914-18 was an artillery war: artillery was the battle-winner, artillery was what caused the greatest loss of life, the most dreadful wounds, and the deepest fear - John Terraine, White Heat

What are ten, twenty, or thirty millions when the British Empire is at stake? This is an artillery war. We must have every gun we can lay hands upon - Lloyd George

Although any war depends on infantry to take and hold ground, the comprehensive nature of the trench system on the Western Front meant that infantry were simply unable to do so without adequate artillery support.

There is a general consensus that artillery accounted for roughly 60% of all casualties, with all other weapons combined making up the remainder.

Artillery was thus the dominant factor in the war. When the artillery failed, like the northern sectors of the Somme on the 1st July 1916, an attack would degenerate into carnage. On the other hand, when the artillery succeeded. like in the southern sectors of the Somme on the same date, the infantry would be able to take most of their objectives without excessive loss.

The real innovation of the war was the development of artillery from its traditional role of direct line of sight fire support to its role of providing predicted, indirect fire capable of hitting an unseen target without preliminary ranging shots. To provide bombardment's to annihilate enemy fortifications with instantaneous fuses to destroy barbed wire, provide creeping barrages very close to advancing infantry, to break up enemy counter attacks, to dominate and suppress the enemy artillery identified through flash spotting and sound ranging.

Everything else was secondary.

This is not to undermine the importance of infantry weapons and tactics, but their effect is overstated - especially with regard to the German 'Strom trooper' tactics. While the territorial gains in Operation Michael were great by the standards of the day, Michael was staged with a gross asymmetry in numbers [1] against an enemy inexperienced in defence, and supported by an artillery preparation of astonishing intensity - 3,500,000 shells fired in 5 hours (that's around 195 shells a second).

While aircraft were somewhat useful for ground attack by the end of the war, their primary utility was reconnaissance. By which we chiefly mean artillery spotting. Is the enemy massing for a counter-attack? Have the infantry lost the barrage? SOS flares? Information could then be radioed to direct artillery fire to where it was needed - much quicker and more reliable than pigeons or runners.

[1] 74 vs. 14 divisions. Lloyd George was deliberately withholding troops so Haig couldn't launch a new offensive. This meant that Brigades were cut from 4 battalions to 3, severely impacting on their ability to rest, train and prepare defences - Command & Control on the Western Front, Sheffield and Todman