OK, I'll bite.
Gary Sheffield in his paper 'Finest Hour? British Forces on the Western Front in 1918: An overview' in Ekins (ed)
1918: Year of Victory, Exisle Publishing, 2010, came up with this list when discussing the success of British units during the Hundred Days (specifically in the context of the 38th (Welsh) Division):
- the devolution of command, with genuine 'empowerement' of commanders at brigade level and below;
- flexibility of commanders at all levels, but especially junior commanders, who were able to respond to changing circumstances;
- the drastic foreshortening of the time needed to plan and execute attacks, which was linked to improved staff work;
- an underdstanding of the importance of, and the ability to carry out, combined arms operations;
- simple but effective tactical doctrine;
- high morale.
(p. 64)[/i]
Sheffield also goes on to point out that the BEF's logistics had been significantly improved after the failures during Passchendaele and how this was extremely important - perhaps the crucial factor - in the Hundred Days; the decentralised nature of British doctrine through the Field Service Regulations and the ability of units to create and disseminate their own solutions to tactical problems; and Haig's role in particular:
I reject Tim Travers' view that Haig and GHQ became effectively irrelevant during the Hundred Days, that Haig was the 'accidental victor'; just as I cannot fully agree with John Terraine's thesis that the victory of 1918 was the vindication of Haig's strategy in 1916 and 1917. An intellectually more satisfying view is that of Robin Prior and Trevor Wilson: that Haig 'proved far more effective as a commander once the sphere of his activities began to diminsh to an extent that brought them within the limits of his capabilities.' (p. 65)
Sheffield makes the point earlier in the piece as well that in assessing Haig's role in the Hundred Days, Foch is almost completely written out of the story. He was ultimately the Allied Supreme Commander, albeit a weak one, and it was he who ultimately seized the moment in July 1918 with the attack on the Marne salient - an attack that both Haig and Petain did not think was appropriate but turned into a great victory, the first of the Allied counterattacks (
not Amiens) and the moment when initative was wrested from the Germans. In a sense that's why I think the whole issue of Haig and the Hundred Days is a bit of a red herring, after Foch's appointment Haig was neither entirely his own master or a direct field commander. Thus as Sheffield demonstrates locating the role he played in the victory is hard. Foch provided strategic direction to all his commanders, though this was not a one-way process - Haig argued Foch round to his own point of few a couple of times, IIRC. Equally Haig was not in direct command of any single operation, as far as I'm aware, with the responsibility falling on his army and corps commanders whom he co-ordinated.
Sheffield also makes another really good point:
Tim Travers has argued that in 1918 the German army 'to a considerable extent defeated itself' by wearing itself out in the offensive battles of the first half of the year. While there is much in this argument, it cannot of course be literally true. Allied soldiers manning artillery pieces and machine-guns, firing Lee-Enfields and Lebels, inflicted those casualties.
It's a fair point, even if the German Army had been gravely weakened by the spring offensives they still had to be beaten. The following essay in
1918 is 'From victory to defeat: The German army in 1918' by Robert T Foley. Foley doesn't provide an exact list like Sheffield as to the reasons why the German Army ultimately agreed to peace in November but I can summarise it pretty easily. Prior to the spring offensives the Germans had already basically ran out of men; at the end of 1917 the Army was 650,000 men short of establishment strength. Transferring men - specifically young men - from the Eastern Front filled out the
Westheer but that was it, no strategic reserve. Similar transfers of horses - still the primary logistical mover for the German - occurred but remained insufficient to make up demand. By the end of the Spring Offensives, as Foley puts it, 'the length of front to be defended by the Westheer had increased by 120 kilometres, while the number of effectives declined.' On top of that casualties had been proportionally higher in NCOs and junior officers, the glue of the army. This fed into a morale crisis brought about by the failures of the offensive to win the war, the crisis back home, and the onset of the flu pandemic. The end result was this:
OHL reckoned that the Westheer was losing at least 80,000 men per month above what could be replaced. Many divisions had battalion field strengths below 400 men. Between March and July, the Westheer had suffered almost three million casualties; of these, nearly a million would not return to service. By the beginning of August, the Westheer found itself 883,000 men below its establishment strength...The OHL was forced by the situation to take the drastic step of breaking up ten divisions to provide manpower to others. (pp. 84-85).
Foley then writes about how this shortage in manpower was exacerbated by new German defensive doctrine that 'deepened' the
Vorfeldzobe to upto 1000 metres - a response to Allied superiority in the
materialschalcht. It was fine in theory but in practice German divisions did not have the manpower to implement it and Foley quotes Rupprecht bemoaning it as leading to small groups of infantry fighting isolated actions which they would inevitably lose. This doctrine coupled with the weak defensive positions occupied by the Germans seems to have lead to the reinvigoration of the infantry; there's little doubt that both the French and the British Commonwealth armies had mastered the combined-arms set piece but as Sheffield points out a significant portion of the fighting done during the Hundred Days were infantry engagements in which the role of both tanks and artillery were minimal. The Australians called it peaceful penetration:
Capitalising on fluid conditions, it was designed to create more room for defence by advancing the line locally and became a competitive private war that gave free rein to individual initiative, patience and bushcraft. A typical instance occurred on a hot may morning neat Morlancourt. Lieutenant Alex Irvine of the 18th Battalion guessed from the stillness in a troublesome machine-gun post opposite that the German were asleep. Organising a raid in ten minutes, he jogged across no man's land with eighteen men and returned in another ten minutes with twenty-two prisoners and the machine-gun. The Australians did not fire a shot and suffered no casualties. The Germans were unaware until that their post had gone. Haig said of the 3rd Division on 9 May:
'During the last three days [they] advanced their front about a mile...The ground gained was twice as much as they had taken at Messines last June, and they had nearly done it with very small losses; some 15 killed and 80 wounded; and they had taken nearly 300 prisoners.'
...Arriving opposite the Australians in mid-June, the 4th Bavarian Division had lost so many by the end of the month that its commander, Prince Franz, Crown Prince Ruppercht's brother, said that the situation was a disgrace to the division. Its relief, the 13th Reserve Division, fared no better. On 11 July, men from the 1st and 4th Battalions cut out over 1000 yards of its front line, takine 120 prisoners and eleven machine-guns without the knowledge of the higher authorities on either side.
(Petersen,
The Anzacs, 350.)
Just as an aside Petersen also has this to say about the nature of command during the Hundred Days:
The pair [Monash and Rawlinson] worked well together. In any case, at this stage of the way, the army commanders and even Haig himself were becoming increasingly less relevant to the day-to-day conduct of operations. The increasing complexity and expertise of the forces they commanded made detailed intervention inappropriate...Like the Canadians under Currie, the Australian Corps under Monash knew its business and Rawlinson applied only the lightest touch. (p. 349).
As Sheffield suggests earlier (along with Prior and Wilson) this can also be broadly applied to British forces although unlike the Dominions it was divisions, not corps, that seemed to be the most stable level in the order of battle.
By the time the Germans arrived back at the Hindeburg Line they didn't have the strength to hold it and consequently Ludendorff threw in the towel. So if I was to come up with a factor for the BEF's success I...wouldn't. I'd suggest Allied success came because their field forces had 'matured', so to speak, and because their opponent had, for the variety of reasons outlined above, been pushed over the precipice. One thing I will say is that while Haig deserves credit for the success of his army I don't think it vindicates his generalship and points to the fact that if you want to understand the whole war you have to look at the armies as an institution - of which leadership at senior levels was just one part.