History of Konohagakure

The Tragedy of Yosuga Pass (ヨスガ峠の悲劇, Yosuka Tōge no Higeki) is a tragic event that happened ten years prior to the start of the Fourth Shinobi World War. Three shinobi from Kirigakure, Suiren, Ganryū and Junsai were sent on a mission to retrieve a document taken by Kumogakure with Iwagakure's assistance. However, when the document was retrieved, the Iwagakure shinobi immediately betrayed the Kiri team on the orders of their Tsuchikage to retrieve the document although it ultimately remained in Kirigakure's possession after Ganryū was pushed from a cliff into a river. However, this resulted in Junsai's death and Suiren sacrificing herself in order to save Ganryū at Yosuga Pass by blocking a barrage of kunai meant for Ganryū. Since that day, Ganryū and other Kiri ninja who disapproved the betrayal had grown to despise Iwagakure and its shinobi. This incident marked the beginning of hostility between Kirigakure and Iwagakure.

During the chunin exams' final stage Konohagakure is invaded by Otogakure and Sunagakure ninja, an attempt to end the peace and prosperity that Konoha alone has enjoyed since the Third Shinobi World War. The invaders are repelled, but Konoha suffers heavy casualties, including Third Hokage Hiruzen Sarutobi. Although Tsunade Senju quickly replaces him as Fifth Hokage, recovery for the rest of Konoha's military forces is slow. The village is understaffed during this time period, leaving it unable to properly respond to events occurring in the interim such as Sasuke Uchiha's defection.