How exactly did Bruno find himself in this situation, despite holding the rank of Generalmajor? Well, if he had to reflect on his actions that led to this point. He would say that he made an error when calculating human nature versus the societal conditioning.
For years in his past life, he had learned that the Empire of Japan and its soldiers were fanatically loyal to their Emperor, so much so that they were willing to charge through machine gun fire with swords in hands in order to achieve victory.
And while that may be true for the individual soldiers that are composed of the Army. The same level of zeal and bravery evidently could not be found in the Japanese leadership who were not compelled by Bruno's challenge and instead used him as a scapegoat to mask their repeated failures.