Tokyo trial experienced a judgment circumscribed for a long period for publication during allied occupation years. This is Justice Pal’s dissenting judgment at the Tokyo trial; endeavored to seek Justice in a different way, justified ‘aggression’ not only considering subjective ends, rather extends beyond that. The present paper does not intend to justify the judgment which exceeds author’s competence, but also tries to extract the notion of aggression where Justice Radhabinod Pal is experimental. Where all acts are not act of aggression, the main concern is to segregate the concept of act of war and the act of aggression. Assertion becomes crucial when certain use of force can be legitimized under sovereign right of self-defense. This paper tends to clarify these ambiguities concerning the notion of aggression relying on Justice Pal’s opinion. Firstly, a progressive attempt has been made to identify the extent of use of force under sovereign right of self-defense, overriding that extent may tantamount to aggression. Then possible means have been drawn to limit the concept of aggression. Finally, the paper would shed brief light on the comparison of Justice Pal’s dissenting opinion with contemporaneous legal framework predominantly concerning the notion of aggression.