First Shinobi World War

The, or simply the , was the first of the great wars that involved the majority of shinobi villages and countries. There are few reliable surviving records of this war, but the experiences of this war led to the birth of the tactics that still form the cornerstone of warfare. It ended with an armistice treaty, but only after all of the Five Great Nations had been seriously damaged.

The war started not long after the system of one shinobi village per country was established by the founding of Konohagakure. To try and maintain a balance of power, the First Hokage divided the tailed beasts among the other five villages when he began his peace talks with them. However, this was not enough to prevent the war, and may have actually increased hostilities.

Both the First Hokage and his brother and successor, the Second Hokage, died during this war. It is unknown how Hashirama died. Tobirama died fighting against Kumogakure's Kinkaku Force, sacrificing himself as a decoy in order for his students to escape. Before doing so he selected Hiruzen Sarutobi for the position of Third Hokage.