Nagara River

The Battle of Nagaragawa (長良川の戦い) is a battle that decided the civil insurrection that arose within the Saitō clan. After entering retirement, Dōsan Saitō began to regret choosing his eldest son as heir. When Yoshitatsu Saitō caught wind of  this growing distrust, he slew his younger brothers and sought to kill his father. Dōsan fled and gathered his forces. Yoshitatsu had better standing among their retainers and extended family, giving him the numeric advantage and ultimately, victory. Nobunaga Oda arrived with reinforcements, but the battle was over before he could help.

Role in Games
This battle first appears in Samurai Warriors Chronicles 3, serving as the first battle of the game. It acts as an introduction to the game's mechanics and establishes the goals/themes of many important players in Nobunaga's era. The battle begins with the Protagonist capturing the southwest garrison, which is guarded by a concealed Shigenao Takekoshi. After his defeat, Toshiie Maeda has to fight Katsuie Shibata and Nobukatsu Oda, who are trying to remove Nobunaga as head of the Oda clan.

Hideyoshi Hashiba steps up in the fight, leading the effort to break the rebellious Saitō's momentum. The monkey can even locate the ambush that Hanbei Takenaka laid with the Mino Trio if he moves over to the central bridge. This allows Hideyoshi, Toshiie, and the Protagonist the chance to block their attempt to ambush Nobunaga's camp. As the Oda/Dōsan Saitō forces push forward, Dōsan Saitō will be slain in his garrison before he can be rescued.

Having lost their initial objective, the victory goal will change to defeating Yoshitatsu Saitō. When Oichi presses the southern lines, she will be surrounded by archer captains, hiding in towers. She will be defeated by them eventually if they are not forced out of their towers and slain. Mitsuhide Akechi defends the gate to the camp Yoshitatsu is located in. Once defeated, only Yoshitatsu remains before the battle is won.

Historical Information
In 1554, Saitō Dōsan formally retired from public life, as was tradition at the time. He appointed his eldest son, Saitō Yoshitatsu, as his heir, despite being the son of a concubine and not Dōsan's primary wife. This retirement was more in legal name than reality, with the son expected to still follow the advice his father gave him. However, a rift began to grow between father and son, as Dōsan regretted appointing Yoshitatsu as head of their clan. The Viper of Mino considered his eldest son too incompetent for the task Dōsan began to favor his two younger sons, Saitō Magoshiro and Kiheiji.

Saitō Yoshitatsu responded to this growing schism by returning to his home castle under the excuse of being deathly sick. He sent Nagai Michitoshi, his uncle, to bring his brothers to see him, claiming his illness was dire enough he needed to impart important words. Once they came to see him, Hineno Hironari cut both brothers down, removing them as possible rivals. When Dōsan learned of his son's actions, he fled Yamashita, his retirement fortress, and began summoning his retainers. Dōsan took up his defense at Tsuruyama Castle, but was only able to gather about 2,700 of his men, while Yoshitatsu convinced 17,500 of their clan to join his side.

Desperately outnumbered, Dōsan called on Oda Nobunaga for aid, as he was his son-in-law and the two had managed to form a pretty good relationship by this point. Nobunaga took a defensive position at Toshima. When Yoshitatsu began to move his forces down the Nagara river, Dōsan moved downriver as well to intercept his son's forces. The Viper led his men across the river to the north bank and engaged Yoshitatsu's forces.

In the initial conflict, Takekoshi Shigenao led the vanguard against Dōsan's retainers, who slew Takekoshi. In response, Nagaya Jinemon issued a challenge for one on one combat, and Shibata Kakunai of  Dōsan's camp responded. Kakunai managed to slay Jinemon and that defeat bolstered  Dōsan's army. At first, Dōsan had the advantage, outnumbered as he was. Yoshitatsu's numbers and many veteran commanders were able to take the advantage back shortly after their initial combat. Nagai Mitsukatsu, better known as Inoue Mtsukatsu, captured Saitō Dōsan alive, taking him back towards Yoshitatsu's camp. However, Komaki Genta cut Dōsan down and claimed his head. Mitsukatsu took Dōsan's nose to prove he had first captured Yoshitatsu's father.

Yoshitatsu sent forces to deal with Oda Nobunaga as soon as the head presentation ceremony was complete, as the Oda forces had not yet managed to reach their location. Nobunaga's forces repelled the first forces to reach them, but once Nobunaga learned Dōsan's fate, he ordered a retreat, legendarily, Nobunaga remained on a boat, ensuring his men could retreat. When the Saitō forces approached, he fired upon them with a matchlock, a weapon the Saitō had not yet experienced, causing them to delay their attack. Nobunaga did manage to secure the still very young Saitō Toshiharu from his brother's purge.

For killing his father, Yoshitatsu became a Buddhist monk, taking the name Hanka. This name was a reference to Tang Dynasty China, where a famous tale of a man who had to kill his father for the greater good was well known. Yoshitatsu used this name to justify killing his father, a grievous sin amongst his contemporaries.