In the book Samurai, Warfare and the State in Early Medieval Japan, Karl Friday focuses on warfare in early medieval Japan. A central thesis could be the political primacy of the imperial court. (Lamers 2005) This period is from the 10th to the 14th century, before the samurai became prominent in Japan and sought to transform themselves into something more than what we think of them today. Friday focuses on five aspects of war in his book; they are the meaning of war, the organization of war, the tools of war, the science of war, and the culture of war. War is a term that is very familiar to us. First, Friday defines war as an armed conflict between gangs or organized bodies. Then you really have to define organized. The gangs could be considered organized. Or how many does it take to organize? Could two people be considered organized? I think legitimate should be included in that definition. Then again, when two gangs fight, they are still waging war. When you look at the organized part, I think you have to think about more people. He also talks about war as a form of communication. Rebel groups seeking to overthrow a government might fit this description. They are not happy with the form of government, so they want to let people know that they are fighting to overthrow the government. This brings us to the concept of just war. Aristotle saw war simply as a means to a higher goal. You don't fight the war just to win the war, there needs to be a purpose to fight the war. He goes on to tell us how others see the just war. The Romans said that war was only just if waged by the state and only accompanied by a declaration of hostility, which meant that war had to be declared on someone. Rebellions and revolutions were not just considered wars. The Japanese did not define when war was just or appropriate. The early Christians rejected war; this came from striving to be more like Christ, the Golden Rule, owing others as you would have them do unto you. Subsequently, Christians could no longer be pacifists; they were supposed to go to war sometime after Constantine became emperor and declared Christianity as the main religion of the time.