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Let's say that (hand-wavery) the Austro-Hungarians manage to hold out on the San-Dneister line as of December 1914, meaning they don't get sucked into fighting for Przemysl and the Germans have to come and rescue them in May with the Gorlice-Tarnow offensive.

Instead, Falkenhayn is free to launch his intended Western Front attack in 1915, probably around late April-early May.
The plans were for an offensive with 3 armies totaling 15 corps (including most of the strategic reserve) to attack between Arras and Albert, one army to guard each flank, one for the central advance.
The offensive was to aim at Doullens, which was deep enough to split the Entente lines and isolate each allied army for a follow up.
The area was chosen for its lack of built up areas for resistance to coalesce around, its open ground conducive to the attack, very poor French trenches, and river lines along the flanks to prevent reserves from moving up. Also there seems to have been decent rail lines from the German side moving forward, meaning that the offensive could be well supplied, while the lateral lines meant that Entente reinforcement would be difficult.

The attack would also happen right around the time of the 2nd Ypres and the last of the Spring offensives in the Artois.
The Ypres battle would be part of the plan, which would act as a distraction to draw off the British, locking their reserves in defending the salient, while also shifting focus away from the intend sector of attack. Waiting for the French to attack in the Artois would also draw off their resistance, making the initial breakthrough successful.

Overall, it seems the Germans were pessimistic about the offensive being a war winner, which is what it was designed to do. However, given all the planning accrued and advantages that would be had by attacking where and when Falkenhayn decided, there is no doubt the initial breakthrough was assured. Whether the Germans could have pushed through to Doullens, that is another matter, and personally I think the advance would have gotten close, but would be stopped.

The French would be forced to fight a mobile battle of the Germans' choice though, which I anticipate would mean they would get chopped up pretty bad in the process. This was also a time when they have limited artillery compared to the Germans or even 1916, plus they had just suffered from several defeated offensives.

While this attack would fail its total objectives and probably cost the Germans, the French would be worse off and set up for another attack, which would be quite a bit more painful than even this offensive.

All information is from this book:
http://books.google.com/books?id=sO...&resnum=1&ved=0CDEQ6AEwAA#v=onepage&q&f=false

What do you all think?
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