This essay represents a part of strategic controlling in scenario-based processes of strategy development - the controlling of assumptions. Strategy controlling is a part of strategy implementation. In the course of the controlling of assumptions one investigates whether the assumptions underlying the chosen strategy (and/or the strategic direction of impact) are still valid, and/or whether relevant aspects were have been ignored. The essay thematically continues the author’s essay “Thinking in Scenarios” as a method of innovative strategic planning (part 1 and 2), where - on a more or less theoretical basis - he demonstrated what scenarios are, how they are generated, and how they can be gainfully applied in the process of strategic management. Two practical examples of use from the field of long-term planning of armed forces were delineated. For the essay the process of the MoD, which had been developed by the Security Policy Division, is especially relevant, because the scenario monitoring described there is based upon this scenario process and/or represents resumption. These scenarios and their development are only addressed insofar as they are important for understanding scenario monitoring. Although basically all scenarios ought to “be kept in mind” when using the scenarios in the strategic management process, it will be helpful (and from a certain moment on necessary in strategic management) to discern in the direction of which scenario and/or group of scenarios the environment develops, in order to realise whether the own strategic direction of impact is still aligned to this environment. The essay tries to contribute to the methods discourse in the field of strategic management in scenario-based security and defence policy strategy development and analysis processes. The conception of Thinking in Scenarios (including scenario monitoring) is a suitable method for generating this kind of progressive knowledge. Knowledge of the own position renders perceiving strategic fault traces and key uncertainties possible and lets this gain of knowledge be known within strategic management. It is eminently conceivable that a strategy is successfully implemented, although the overall conditions require some “readjustment”. Here it is absolutely vital that this course correction does not happen too late. Knowledge of the own position on the “map of the future” renders a timely change of the direction of impact possible in case of a change of the strategy assumptions. In case of a flexible strategy, the systematic assessment of the future developments in the future space offers the opportunity to timely discern the time period when a more accurate strategic direction of impact ought to be developed, or when a different strategy option should be adopted. Neither scenarios nor a superimposed scenario monitoring, however, can forecast the future exactly, nor do they describe the “only true future”. Scenarios are models of thought with which we are able to approach the future challenges and prospects.