What if starting with Tōgō Heihachirō at prime of his influence on the navy the IJN strictly enforced the rules of war on them selves and IJN Land forces. To point where breaking the rules of war is considered by the IJN so dishonorable that being convicted causes the convict to commit ritual suicide and if they are not fragged. Basically the they still fight every bit as hard as OTL just with out violating rules of war. The IJA is every bit as nasty as OTL. What does this do? One I can think of is that the Japanese declaration of war arrives on time and is actually a declaration of war.