When an engagement is expected, the different elements, each in route column, are directed upon their several objectives, i.e., the column is _developed for action_. This is done because it is necessary to gain a start over the enemy in deployment and advantageous to move in route column. Thus a =development for action= (_Entfaltung_)[217] is nothing but an extension of front accomplished by breaking up the original route column into a number of separate columns. The latter march on diverging lines and can generally remain in route column. Deep column should not be formed unless an immediate extension is not anticipated. During the development for action, preparations should be made providing for the necessary depth of the combat formation. [217] The German I. D. R. make a distinction between extension of front, “development for action” (_Entfaltung_, pars. 315 and 466), and “distribution in depth” (_Gliedern_, pars. 287-291 and 427). The term “to form for attack” (_Auseinanderziehen_, par. 241), means that troops are given a combat formation both as regards frontage and depth. When the necessity for engaging can be foreseen, the concentration into an assembly formation should be avoided, since it generally entails a loss of time and energy, and the development for action chosen instead. (Par. 315 German I. D. R.). The latter has the additional advantage of affording a higher degree of readiness for action without letting the troops get out of hand. It should be practiced not only from route column but also from assembly formation.[218] [218] See the defeat of the Russian Reserve Brigade under Orlov on September 2nd, 1904, at Liao Yang, in _Angriffsverfahren der Japaner_, by von Lüttwitz. The development for action should begin as soon as there is danger of getting under effective artillery fire. The length of time required for going into action may be reduced by shortening the route column (by concentrating the troops into deep column); by forming several route columns abreast, unless column of sections has already been formed; by clearing the roads of troops; by marching across country; by indicating beforehand on which side of the infantry the artillery is to be brought up (pars. 315-323 German I. D. R.); and, finally, by directing the heads of the various elements upon their respective objectives. (Development for action).