- Of a fixed base of operations.
- Of a principal objective point.
- Of fronts of operations, strategic fronts, and lines of defense.
- Of zones and lines of operations.
- Of temporary strategic lines and lines of communications.
- Of natural or artificial obstacles to be overcome or to oppose to the enemy.
- Of geographical strategic points, whose occupation is important, either for the offensive or defensive.
- Of accidental intermediate bases of operations between the objective point and the primary base.
- Of points of refuge in case of reverse.
For illustration, let us suppose the case of France invading Austria with two or three armies, to be concentrated under one commander, and starting from Mayence, from the Upper Rhine, from Savoy or the Maritime Alps, respectively. The section of country which each of these armies traverses may be considered as a zone of the general field of operations. But if the army of Italy goes but to the Adige without concerted action with the army of the Rhine, then what was before but a zone becomes for that army a theater of operations.
In every case, each theater must have its own base, its own objective point, its zones and lines of operations connecting the objective point with the base, either in the offensive or the defensive.
It has been taught and published that rivers are lines of operations par excellence. Now, as such a line must possess two or three roads to move