Clearly defined sections of the battlefield (par. 475 German I. D. R.) and definite combat tasks, each complete in itself (par. 293 German I. D. R.), are assigned to the tactical units to be employed in the first line (battalions in case of a regiment; regiments, as a rule, in case of a division). In attack, the order indicates the front upon which each one of the larger units is to deploy and what portion of the hostile position it is to attack. This demarcation defines the extent of the combat sections (par. 371 German I. D. R.), within the limits of which the particular unit must make the most of the accidents of the ground. In carrying out these combat tasks, unity of action is ensured by the mutual coöperation of the tactical units fighting abreast of each other (par. 475 German I. D. R.), and by the designation of a unit upon which the others regulate their movements, without, however, thereby being hampered in their endeavor to advance. (Base unit of combat). Moreover, by employing his reserves, the commander “can shift the decisive point of the action to any place desired, reinforce where he deems it advisable, equalize fluctuations of the combat, and, finally, bring about the decision.” The first orders--those for putting the troops in motion in the desired direction--are usually verbal; more detailed orders, which are the rule from the brigade on up, are issued subsequently. (Par. 274 German I. D. R.). In most cases, the commander knows quite well what he wants, but only the effort required in expressing in writing what he desires to say, enables him to reproduce his thoughts with the necessary clearness. Even in peace maneuvers, the officer who issued an order and its recipients quite frequently disagree as to its interpretation; the superior remembers only what he desired to say at the particular moment, but not the language in which the order was couched. Written orders minimize the possibility of a misunderstanding. They have the further advantage that the recipient has in his possession a document to which he can always refer in case of doubt.