Recognition of New Problems. The supervision of the planned action, as the fourth step (see Chapter V) of the exercise of mental effort in the solution of military problems, therefore constitutes in itself a problem, in that it involves fundamentally the ability to recognize the existence of new situations which present new problems for solution. To recognize such new problems requires a constant, close observation of the unfolding of the original situation. Only an alert commander can invariably determine whether the situation is unfolding along the lines which he desires and as promulgated in the directives formulated in the third step (see Chapter V and Chapter VIII). In effect, the commander, after action has begun, considers the changing situation as a variable in the problem presented by the original situation. With the march of events he is, therefore, constantly critical to detect whether variations in the original situation are in accordance with his design or whether these variations demand a departure from his plan. Nature of Readjustments Required. If variations in the original situation are in accordance with his design, the commander has the assurance that all goes well, and that the unfolding of the situation is following his intent. However, if this is not the case, changed circumstances may demand recognition of the fact that a new problem has presented itself. In this event a new incentive, arising from the demands of the situation, calls for the solution of the new problem by the procedure distinctive of the first step (Chapter VI). Should directives of higher authority introduce a new incentive, the commander solves such a new problem, also, by employing the procedure distinctive of the first step. On the other hand, the commander may find that the changed situation motivates merely a modification of his previously determined operations and of his directives already in force. In other words, while his basic problem (Chapters V and VI) may remain the same, need may arise for certain deviations from the decisions arrived at in the first and second steps of its solution. Should this be the case, each such problem will require solution by a return to the procedures described (Chapter VII) with reference to the second step. In the event of a demonstrated need, not for any change of plan, but for a clarification of directives, the procedure involved is that distinctive of the third step (Chapter VIII). The commander may not safely view the succession of events with complacency, even though the situation appears to be unfolding according to plan. Perhaps the enemy may be purposely lessening his opposition, in order to prepare for the launching of an offensive elsewhere. As the situation unfolds, everything is viewed with intelligent suspicion.