The French know they are about to be attacked. The Austrian army is massing on the borders and intelligence are reporting anything up to 82,000 troops dispersed amongst the towns of Wimperk. Budweis and Zweittel in the forests north of the Danube and a further 56,000 deployed behind the River Inn at Braunau, Schaerding and Lambach.
Expected enemy strategy
Taking the limitations of the road system into account the most likely strategy for the Austrian Army will be to advance directly on Passau from the North in order to establish a concentration of troops West of the Inn before marching in force on Landau and Deggendorf to secure a crossing of the Isar. At the same time it is likely that at least one enemy Corps will attempt to seize the supplies stored at the French Depot in Munich.
Having secured a crossing of the Isar and seized our forward supply depots one would expect the Austrians to attempt to force a decisive victory over both Davout's III Corps and Lefebvre's VII Corps before our main army can move to reinforce either.
If successful this would match Davout and Lefebvre with 82,000 men against an Austrian force of approximately 110,000. Whilst in the South Lannes with 22,500 men would face approximately 28,000 troops.
Intended French Strategy.
It seems unlikely that we will be able to defend our forward depots along the Isar and so these will be withdrawn to deny the supplies to the enemy whilst our forces concentrate to the rear.
Davout and Lefebvre will withdraw to Ingolstadt, whilst Lannes at Augsberg will be reinforced by the main army of observation under Massena and Vandamme's Wurtemberg Corps from Ulm.
At the same time the centre of operations will be moved north to Donauworth in order to expliot the better road network and shorter communication distances. The depot at Ulm will be reduced and the supplies redirected to Inglostadt and Augsberg.
Both Ingolstadt and Augsberg have good road networks and the intention is to expliot these to frustrate Austrian movements.
If the Austrians attempt to force the Danube at Ingolstadt then Napoleon will advance on their left flank and communications from Augsberg. If they attempt to attack Augsberg then Davout will move against their right flank and communications from Ingolstadt. Finally if a decisive victory is acheived then the road network will allow both Napoleon and Massena to concentrate their forces quickly to expliot the advantage.
Thats the plan anyway. We shall see if it works in practice.
