Why did Katsuyori go to the Battle of Nagashino and lose?

The relationship with the older seniors that troubled Katsuyori after he succeeded as the head of the family

　The biggest issue for Katsuyori, as the new leader, was his previous position.

　Many daimyo in the Sengoku period would announce their retirement and pass on the leadership when their eldest son reached around 20 years old. Even though it is called retirement, it does not mean a life of leisure but rather a continuation of the highest authority. The purpose was simply to divide the roles between father and son and facilitate a smooth transition of leadership.

　However, Shingen never retired until his death. Whether it is Yoshinobu or Katsuyori, there is little evidence that they inherited authority in domestic affairs. The same was true in diplomatic matters and in military matters, as Katsuyori only acted as successors and never entered into battle as a commander until Shingen’s death.

　At the time of his succession, Katsuyori was 28 years old. In contrast, the senior retainers appointed by Shingen were around 50 to 60 years old. Although Katsuyori had been Shingen’s heir, he was treated as almost the same level on the battlefield. Therefore it is not easy for the seniors to suddenly change their mindset to regard Katsuyori as their lord.

　In other words, at that time, Katsuyori was troubled by his relationship with his retainers, who were about the same age as his father, and also by the wounds of the Yoshinobu incident.

　Katsuyori needed to take an aggressive stance and accumulate victories to demonstrate his “achievements.” In 1573 (the first year of Tensho), when Shingen died, Nobunaga launched a counterattack which destroyed countries such as the Asakura, Asai, and Miyoshi clans and forced Ashikaga Yoshiaki to leave Kyoto. During this period, Katsuyori was unable to provide any support to his allies. The fact weighed heavily.

　In 1574, Katsuyori Katsuyori launched an offensive in the eastern part of Mino Province and Tōtōmi Province. In the latter, he forced the surrender of Takatenjin Castle, which had initially surrendered to Shingen but subsequently allied with the Tokugawa.

　In 1575, support requests arrived from the Honganji sect and Miyoshi Nagayoshi, indicating that an invasion by Nobunaga was imminent. Since Katsuyori had failed in the previous year to rescue the sieges of Nagashima, it was essential for Katsuyori’s reputation as a daimyō of the Sengoku period to provide support this time.

　Around the same time, the retainers of Matsudaira Nobuyasu, Ieyasu’s eldest son and the lord of Okazaki Castle in Mikawa, and Ooka Yashiro, the magistrate of Okazaki, offered to collude with Katsuyori. They planned to support the Honganji and Miyoshi clans by conquering Okazaki Castle and invading Owari.

　However, this plan was foiled when Ooka and others were found to be in league with Katsuyori and executed. Katsuyori therefore changed his target to Nagashino Castle in Mikawa, which was recaptured by Ieyasu after the death of Shingen.

　Meanwhile, Ieyasu succeeded in persuading the reluctant Nobunaga. This marked that, for the first time, Nobunaga and the Takeda clan would meet on the battlefield.

The Battle of Nagashino resulted in enormous casualties

　Nobunaga’s greatest concern was the conquest of Honganji Temple. the casualties of his own troops, he gathered foot soldiers armed with guns from each of his retainers.

　Nobunaga was also concerned about the cavalry of the Eastern forces. The pastures for horses were concentrated in eastern Japan, and daimyos of eastern Japan were skilled in fighting on horseback. However, there were few pastures in the west of Nobunaga’s territory, Owari and Mino, and daimyos there were not good at fighting on horseback.

　On the other hand, the Takeda clan also emphasized the use of guns, but they did not have a port where they could import gunpowder or lead, which are used for gunpowder.

　The Battle of Nagashino is often depicted as a confrontation between the Oda arquebusiers and the Takeda cavalry. However, this is a misconception that applies the differences in warfare between the eastern and western regions directly to the Oda and Takeda clans.

　Nobunaga, who advanced towards Arumihara located west of Nagashino Castle, ordered his troops to appear as if they had fewer reinforcements. He had triple-layered horse barricades built and took shelter within them. Katsuyori, trying to assess the situation, judged Nobunaga to be weak and underestimated his forces. In reality, while the Takeda forces that marched to Arumihara numbered around 12,000, the combined forces of the Oda and Tokugawa clans amounted to approximately 40,000.

　Nobunaga ordered his men to concentrate on firing their guns from within the fence. On the morning of May 21st, Ieyasu’s retainer Tadatsugu Sakai broke the siege line at Nagashino Castle, cutting Katsuyori off from the rear.

　The battlefield at Minohara had narrow roads, making it unsuitable for cavalry maneuvers. Additionally, the Oda-Tokugawa forces, who concentrated on arquebus fire from inside the fence, outnumbered the Takeda forces. Although the Takeda forces managed to breach some sections of the barricades, they realized that they were losing and retreated approximately six hours later. Pursued by a large enemy army from behind, the exhausted Takeda forces suffered extensive casualties, ranging from high-ranking officers to foot soldiers.

Editorial supervision and text by Kazuhiro Marushima

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