This study examines the explanatory value of Robert Leonhard´s theory of combined arms on the battles of Bardia and Arnhem during the second world war. The battles chosen are very similar in the context of force strength and assets of arms, however the outcome of the battles differ in terms of tactical success. Since no previous research has been done specifically on the effect of combined arms when the attacking force is numerically smaller, but alike with the defender on all other factors, a research gap was found and therefore an opportunity for a study. As many of the Swedish armed forces doctrines are similar with the theory used, there is significant interest in examining to what extent the theory can explain the battles outcome studied, since these battles are similar to ones which the Swedish armed forces may end up fighting in the future. The results from the study show that Leonhard´s theory can explain the outcomes of each battle, since the forces who apply the principles of the theory also gain tactical success. Although the results support the explanatory value of the theory, there is reason to believe that it is linked to probability rather than deterministic causality, since not all principles in the theory were found to have been applied in the empirical cases studied. In order to further examine the theory of Robert Leonhard, more studies have to be done using other cases for the analysis.