Under the German organization then existing the preliminary to all active operations was of necessity full and complete mobilization. Then followed transport by road and rail to the line selected for the "strategic deployment," and it was essential that no part of these operations should be disturbed by action on the part of the enemy. But no such delay imposed itself of necessity upon the French, and a vigorous offensive was so much in harmony with their traditions that the German plan had to be framed so as to meet such emergencies. On the whole, Moltke concluded that the enemy could not undertake this offensive before the eighth day after mobilization. At that date about five French army corps (150,000 men) could be collected near Metz, and two corps (70,000) near Strassburg; and as it was six days' march from Metz to the Rhine, no serious attack could be delivered before the fourteenth day, by which day it could be met by superior forces near Kirchheimbolanden. Since, however, the transport of the bulk of the Prussian forces could not begin till the ninth day, their ultimate line of detrainment need not be fixed until the French plans were disclosed, and, as it was important to strike at the earliest moment possible, the deployment was provisionally fixed to be beyond the Rhine on the line Wittlich-Neunkirchen-Landau. Of the thirteen North German corps three had to be left behind to guard the eastern frontier and the coast, one other, the VIII., was practically on the ground already and could concentrate by road, and the remaining nine were distributed to the nine through railway lines available. These ten corps were grouped in three armies, and as the French might violate Belgian neutrality or endeavour to break into southern Germany, two corps (Prussian Guard and Saxon XII. corps) were temporarily held back at a central position around Mainz, whence they could move rapidly up or down the Rhine valley. If Belgian neutrality remained unmolested, the reserve would join the III. army on the left wing, giving it a two to one superiority over its adversary; all three armies would then wheel to the right and combine in an effort to force the French army into a decisive battle on the Saar on or about the twenty-third day. As in this wheel the army on the right formed the pivot and was required only to stand fast, two corps only were allotted to it; two corps for the present formed the III. army, and the remaining five were assigned to the II. army in the centre. When (16th-17th July) the South German states decided to throw in their lot with the rest, their three corps were allotted to the III. army, the Guards and Saxons to the II. army, whilst the three corps originally left behind were finally distributed one to each army, so that up to the investment of Metz the order of battle was as follows: Headquarters: The king of Prussia (General v. Moltke, chief of staff).