The Toishi Debacle

Background — The Invasion of Shinano and the Defeat at Uedahara

Takeda Harunobu (later Shingen), the Sengoku daimyo of Kai Province, had been steadily advancing into Shinano Province since Tenbun 10 (1541), the year he took over the family headship after exiling his father, Nobutora, to Suruga. After subduing the Suwa, Ina, and Saku areas one after another, Harunobu's next target was northern Shinano, which controlled the Chikuma River basin. The man standing in his way was Murakami Yoshikiyo. In Tenbun 17 (1548), Harunobu clashed with Yoshikiyo, the powerhouse of northern Shinano, at Uedahara and suffered a crushing defeat that cost him senior retainers including Itagaki Nobukata and Amari Torayasu. That same year, Harunobu avenged himself by defeating Ogasawara Nagatoki at the Battle of Shiojiritōge, but his defeat at Yoshikiyo's hands is said to have remained deeply etched in his mind.

In the 7th month of Tenbun 19 (1550), after further defeating Ogasawara Nagatoki and advancing his control of central Shinano, Harunobu moved to undermine Yoshikiyo's power in northern Shinano by attacking Toishi Castle (also written Togoishi, in present-day Ueda City, Nagano Prefecture), an important forward outpost of Yoshikiyo's. Toishi Castle was the forward stronghold guarding Yoshikiyo's home base of Kazurao Castle. Taking it would let Harunobu both avenge Uedahara and decisively secure control of northern Shinano, killing two birds with one stone.

Murakami Yoshikiyo was head of the Murakami family, a prominent northern Shinano clan said to descend from the Seiwa Genji line. He had driven Harunobu back at Uedahara and was known as one of the most skilled commanders in Shinano at the time. Yoshikiyo's domain extended across the Chikuma River basin. With Kazurao Castle as his base, he had arranged several outposts around it, including Toishi Castle, forming a layered defensive network. For Harunobu, Yoshikiyo was the greatest barrier to completing the conquest of Shinano.

The Forbidding Terrain of Toishi Castle and the Takeda Assault

Toishi Castle was a stronghold whose terrain was as steep as its name, which means "grindstone." Cliffs rose to the east and west, and the only possible approach was from one direction, the southwest. Its garrison numbered only about 500, but protected by this natural fortress, the castle was known as a stronghold that would not fall easily. On the 9th day of the 9th month of Tenbun 19, Harunobu's Takeda army of about 7,000, with senior retainer Yokota Takamatsu's unit as vanguard, launched a full-scale assault on Toishi Castle.

The Takeda forces relied on their overwhelming numerical advantage and kept up the siege, but the castle's firm defenses did not give way, and the capture stalled. As the siege dragged on, Murakami Yoshikiyo left his home base at Kazurao Castle with a relief force of about 2,000 men, threatening to pincer the Takeda army. On the last day of the 9th month, the Takeda finally gave up the attack and decided to withdraw.

Disaster in Retreat — The Death of Yokota Takamatsu

However, this retreat became the greatest tragedy for the Takeda. The castle garrison and Yoshikiyo's main relief force coordinated to launch a fierce pursuit of the retreating Takeda army. On the 1st day of the 10th month, the disorganized Takeda troops were routed in several places and suffered heavy losses. Many officers and men fell in this retreat, including senior retainer Yokota Takamatsu, who had been leading the vanguard. The Takeda army as a whole suffered a major defeat with roughly 1,000 dead and wounded, an extraordinary toll for the time. This series of defeats is remembered as the "Toishi Kuzure" (Toishi Debacle) and is known as Takeda Shingen's second major defeat, after the Battle of Uedahara.

Yokota Takamatsu is said to have come from Kōka District in Ōmi Province. He entered Kai in the time of Harunobu's father, Nobutora, and served the Takeda as a veteran ashigaru taishō (foot-soldier commander). Skilled with the bow, he had built up numerous military exploits on the Shinano vanguard front. His death in the confusion of the retreat is said to have dealt a great shock to the whole Takeda army. Harunobu later lamented his loss, telling his attendants, "If you want to become a man of martial spirit, be like Hara Mino (Hara Toratane) and Yokota Bitchū (Takamatsu)." This anecdote also survives. It shows that the Toishi Kuzure was not merely the failure of a single castle assault, but a battle that dealt severe damage to the commanders at the core of the Takeda house.

Sanada Yukitaka's Stratagem and the Fate of Toishi Castle

Even after the Toishi Kuzure, Murakami Yoshikiyo continued to hold Toishi Castle, but the Takeda pursued a means other than direct assault. Sanada Yukitaka (also written Yukitsuna), who served the Takeda as a Shinano vanguard lord, was a local lord based in Sanada district of Chiisagata District, and he knew the networks and conditions of the region well. Rather than relying on force, Yukitaka worked through stratagem within the castle to bring it over to the Takeda side. In the following year, on the 26th day of the 5th month of Tenbun 20 (1551), Toishi Castle finally fell into Takeda hands without a battle.

The capture, in which a castle that had dealt a crushing defeat to a direct assault was opened without bloodshed through stratagem in barely a year, was passed down as an anecdote symbolizing Sanada Yukitaka's cunning. It also became an occasion for the Sanada clan to be valued within the Takeda house. Harunobu himself is said to have marveled that Yukitaka had taken a castle that even a large army could not take, using only a small amount of stratagem. From then on, the Sanada held an important role in diplomacy and stratagem as one of the few senior Shinano vanguard lords among the Takeda retainers.

Murakami Yoshikiyo's Decline and the Road to Kawanakajima

The loss of Toishi Castle meant that Yoshikiyo had lost an important forward bastion guarding his home base at Kazurao Castle, and his defensive line was forced to pull back substantially. Unable to withstand Takeda pressure, Yoshikiyo finally abandoned his home base of Kazurao Castle in the 4th month of Tenbun 22 (1553) and fled to Echigo Province to seek the protection of Nagao Kagetora (later Uesugi Kenshin). Kagetora's decision to campaign in Shinano in response to Yoshikiyo's flight became the direct trigger for the Battles of Kawanakajima, which would be fought intermittently over the following decade and more. Thus, the contest over a single outpost became a major turning point that developed into the fated confrontation between the Takeda and Uesugi, two rivals contending for Shinano.

The Lasting Lessons of the Toishi Kuzure

The Toishi Kuzure has often been cited in later military studies and castle research as a case showing that a small garrison holding strong terrain could repel a besieging army many times its size. At the same time, the battle is positioned as a striking contrast that illustrates both the limits of direct frontal assault and the Sengoku-period tactical philosophy of taking castles through stratagem and intrigue. Shingen himself is said to have taken this crushing defeat as a lesson. In his later campaigns to subdue Shinano, he did not cling to direct assault and came to value flexible strategy that mixed stratagem and diplomacy with military force. In fact, in the later Shinano campaigns, he more often won over local lords through stratagem and marriage policy than through direct assault. The view that the bitter experience of the Toishi Kuzure shaped Harunobu's own strategic outlook is widely shared in current Takeda clan research.

Today, the ruins of Toishi Castle have been developed as a historic site in Ueda City, Nagano Prefecture, and the castle grounds offer a sweeping view over the Ueda Basin. The steep terrain still preserves the appearance of the stronghold it once was. As the stage of a major defeat suffered by Takeda Shingen, the site continues to draw the interest of visiting history enthusiasts.

The Later Fortunes of the Sanada — From Shinano Vanguard Lords to a Daimyo House

The Toishi Kuzure and the bloodless capture of Toishi Castle that followed under Sanada Yukitaka are regarded as the starting point of the Sanada family's rise, later known as the "Three Generations of Sanada." Yukitaka's son, Sanada Masayuki, distinguished himself as a Takeda retainer in operations toward Kōzuke. After the fall of the Takeda house, he became an independent Sengoku daimyo and, based at Ueda Castle, twice repelled large Tokugawa forces. Masayuki's son, Sanada Nobushige (Yukimura), was remembered for generations as a clever commander who gave the Tokugawa side a hard time in the Ōsaka Campaigns. The early success of stratagem around Toishi Castle is also said to be one of the origins of the Sanada family's tradition of excelling at stratagem and information warfare.