Kasugayama Castle

Kasugayama Castle (春日山城) is one of the Uesugi's known castles built in Echigo. Kenshin inherited it as a part of his Nagao family heritage and used it as his main dwelling. The Uesugi Manor, the office and residence of the Echigo-Uesugi Governor Norimasa Uesugi, once stood near the base of the castle.

After Kenshin's death, the castle grounds became one of the major battlegrounds for the civil war between his two potential heirs, Kagekatsu and Kagetora. Kagekatsu held himself within the castle, and Kagetora besieged it while stationing himself within the Uesugi Manor. This conflict is often called The Otate War (御館の乱, Otate no Ran), "Otate" being an archaic name for Uesugi Manor.

Koei's adaptations of the conflict mainly center the siege of Kasugayama Castle.

Samurai Warriors
The castle siege for Kasugayama Castle often results in Kagetora's immediate demise in this series.

Players side with Kagekatsu's forces in Samurai Warriors Chronicles and Samurai Warriors 4. In both versions of the conflict, his forces have to flee from Kasugayama Castle due to a fire attack. Their goals are to rout the Hōjō and Date forces, and convince the Takeda forces to defect to corner Kagetora and Aya. Kotarō and his clones pose a major obstacle to the main camp defenses.

In the Chronicles version, Kagekatsu's forces make an additional effort to detain Norimasa before he flees. Kagetora leaves the Uesugi Manor and attempts to reach Sameoka Castle to regain a second wind. Aya acts as the last character that needs to be routed. The fourth title replaces Norimasa's retreat with Lady Hayakawa, Kai, and Kojūrō's appearances for their respective forces. Aya acts as a decoy for Kagetora's desperate last charge for Kasugayama Castle. She must be beaten in order to reach Kagetora in time.

Aya's story in Sengoku Musou 3: Moushouden allows players to fight for the Kagetora side of the conflict. Players are asked to keep morale high by protecting Kagetora from immediate threats. If they succeed, their next objective is to conquer the west to make way for the Hōjō reinforcements. Yukimura's charge towards the main camp occurs regardless if the player fails or succeeds this objective. When Yukimura and Kunoichi are routed, Nobunaga and the Oda army automatically enter the battlefield as third-party forces. Nobunaga's defeat causes the Oda to flee and is needed to trigger Kanetsugu's charge, which opens the gates for Kagekatsu's main camp. Kanetsugu attempts to stop the player's victory twice.

In Samurai Warriors 4-II, this battle is present in Hayakawa's story where this stage is instead playable on Kagetora Uesugi's side, where although his forces have the upper hand due to the Hojo's aid, the Takeda's betrayal along with constant ambushes led by Masayuki's forces and Kunoichi lead Kagetora to retreat to the southwest and escape his brother's wrath, having to defeat Kanetsugu and Kagekatsu to retreat from the bloodbath. With the help of the Hojo forces, he escapes, only for Kai and Lady Hayakawa to later find out he was betrayed by some of his retainers and cut down at his own castle.

Nobunaga's Ambition
Nobunyaga no Yabou showcases this battle during the Bishamonten no Hata scenario. Players could read key events that occur for the conflict and fight against the dead to grant their souls rest.

Historical Information
The details over which son Kenshin chose as his true successor, the exact parties involved, and the exact length of the conflict are disputed. Exact details can be found from records outside the Uesugi, but the internal workings for the conflict are varied. What can be verified is that Kenshin became deathly ill on April 14, 1578 and died in his sleep five days later.

In the following weeks, his adopted sons were presumed to be antagonistic towards one another. On April 30, Kagekatsu relocated to the main keep of Kasugayama Castle and confiscated the family treasury, gold storehouses, and documents which were used by Kenshin. He sent a letter that proclaimed him as his father's successor to the neighboring provinces. Open warfare was not known to be taking place at this time, but the letter includes a vague declaration of war "to dispel enmity". Kagetora, who was stationed within the third manor of the castle grounds, prepared his domain for an attack. Legends state that the brothers and their followers sent constant threats to one another during this time.

According to the nearby Ashina, the brothers were locked in a stalemate through the majority of May, each gathering allies towards their cause. Kagetora appealed to aristocrats and nobles, gaining the respect of Kenshin's adoptive father, Governor Uesugi Norimasa, and his followers. He would later call upon his biological family, the Hōjō, and their curtain of eastern allies: the Takeda, the Date, the Ashina and the Daihōji. Kagekatsu had members of Kenshin's inner circle or his loyalists backing him —retainer families like the Naoe, the Yamayoshi and the Higuchi. Exact numbers for either side are unknown. Common opinion held by locals and legends generally state that Kagekatsu's forces started outnumbered.

By June 10, war between the brothers began. Each side took an offensive and clashed on and off for eight days. Kagetora relocated him and his family to Norimasa's shelter at Uesugi Manor. He sent a request for Hōjō relief to attack Kagekatsu's flank and ordered his followers to surround Kasugayama Castle. Kagetora's troops were ordered to regularly harass the defenders through fire attacks or arrow volleys. Kagekatsu was relocated to Sakado Castle sometime before the fighting commenced and continued to oversee the situation.

The Hōjō could not send their troops to Echigo because they were simultaneously involved in a war between the Satake and Utsunomiya. Once he received the news, Kagetora appealed to the Takeda in late June. Takeda Katsuyori agreed to the request by sending 20,000 men towards the Echigo boarder. Kagetora received a positive reply from Date Terumune and the Ashina, who came towards Kagekatsu's flank from Oshu. Shibata Shigeie delayed them at Yasuda Castle and the main defenders held a strong defense at the main keep. Momentum was in Kagetora's favor, but his side were losing numbers quickly and could not penetrate Kagekatsu's defenses.

Katsuyori proposed a peace treaty between the brothers in July. Around this time, it is argued that Katsuyori thought Kagekatsu was a worthy successor due to the later marriage alliance between Kagekatsu and Katsuyori's younger sister, Kikuhime. The armistice arranged by the Takeda was argued to be a cordial formality, rather than a sign of good faith. With the Takeda alliance on his side, Kagekatsu was able to directly contact his followers to reassess Kasugayama Castle's defenses.

Although a peace treaty was signed and mediations began, peace was reduced to shambles when Katsuyori received news that Tokugawa Ieyasu was laying siege to the Takeda's Tanaka Castle in Suruga. A portion of the Takeda troops remained in Echigo while Katsuyori abandoned peace talks in September. The remaining Takeda chose to side with Kagekatsu due to their bias against the Hōjō. Simultaneously, the Hōjō were free and sent troops along Mikuni Pass. Kagekatsu's troops predicted their march and repelled them. After a few days of fighting, the Hōjō troops withdrew when the winter storms blew into Echigo.

Kagetora, meanwhile, was made aware of his first named deserter, Nagao Kagenao. Kagenao's estate was reduced to ruin because of the civil war and he used this chance to defect to the Oda. Morale on Kagetora's side plummeted when supplies ran low and when Katsuyori's collusion with Kagekatsu became apparent with the marriage alliance between Kagekatsu and Kikuhime. His forces tried and failed to infiltrate Kasugayama Castle for supplies. He could not provide decent care for them nor could he quell the internal riots and bickering that took place during the rest of the year. Before the winter storms could hit in full force, Kagekatsu held the majority of the retainers' support.

On February 26, 1579, after the brunt of the blizzards had lifted, Kagekatsu suspected that the nearby Hōjō would surround him again and ordered his troops to attack the Uesugi Manor. Major casualties were dealt to Kagetora's side and a fire attack had burned through their fortifications. They were barely able to hold their ground. Norimasa left the Uesugi Manor on April 12 with the motive of arranging another peace treaty, taking Kagetora's eldest son, Dōmanmaru, with him to be a political hostage to Kagekatsu. Both were killed on the way. It is often said they were killed by Kagekatsu's men (either they were assassinated together or Norimasa was captured and then ordered to commit suicide), but there are stories that name Kagetora's followers responsible; they cut the pair down after accusing them as traitors. Alternatively, an outside party from Shinano has been blamed for the killings.

Realizing the situation was lost, Kagetora and his remaining family and followers fled the Uesugi Manor to head towards Odawara Castle. They rested at Sameoka Castle and were betrayed by Horie Munechika. His remaining loyalists were killed, and Kagetora and his remaining family committed suicide together a week later.