The Secrets Behind the Unity and Strength of the Tokugawa vassals – Why Did  the Samurai from Mikawa conquer the Realm?

Tokugawa Ieyasu, the main character in the 2023 historical drama “What Will Ieyasu Do?” (in Japanese : “Dousuru Ieyasu”) will be played by Matsumoto Jun. Surrounding him are the loyal vassals who have supported him since the Mikawa period. The Tokugawa vassals are renowned for their unwavering loyalty to their lord, strong unity, and tenacious combat skills. Although they may have a modest impression compared to the vassals of the Oda and Toyotomi clans, they became the driving force behind Ieyasu’s success in conquering the chaotic Sengoku era and achieving supremacy. We will thoroughly explore the character traits of the Mikawa province samurai who formed the core of the Tokugawa vassal group, their characteristics, their organization, their achievements, and the secrets behind their strength.

The Evolution of Tokugawa vassals alongside the growth of Ieyasu 

The three key elements that characterize the Tokugawa vassals : “loyalty”, “unity”, and “combat skills” – were established as Ieyasu evolved from being a hostage during the Oda and Imagawa reign, to becoming an independent daimyo (warlord) and eventually rise as Shogun. Ieyasu’s control of his vassal changed and evolved over time and according to the circumstances. 

In the early days, during the period when Ieyasu was a hostage with 250 men, the group gradually took shape when they got released, returned to Okazaki and then unified the Mikawa province. Under the command of retainers such as Tadatsugu Sakai and Ishikawa Ienari (later known as Kazumasa), the vassal group was formed around local samurai clans. They engaged in territorial disputes with the Imagawa and Takeda clans over the control of Mikawa and the surrounding provinces of Totomi, Suruga, Kai, and Shinano. During this period, direct vassals and military commanders from Mikawa were independently stationed as castle-holding vassals, entrusted with the management of their own territories. Additionally, Honda Tadakatsu and Sakakibara Yasumasa were stationed at Hamamatsu Castle as samurai commanders. Notably, Ii Naomasa, who hailed from Totomi and was recognized for his abilities by Ieyasu, also emerged during this period. Additionally, the “O-Bangumi” group which served as Ieyasu’s personal bodyguards, was established from these standing armies.

While cooperating with Toyotomi Hideyoshi’s campaign for national unification, Ieyasu transferred to the Kanto region following the fall of the Hojo clan in Odawara in 1590. Although many of his loyal vassals were upset by this decision, Ieyasu utilized this dissatisfaction to strengthen the bonds among his vassals and foster unity. To administer the new territory, Ieyasu assigned 42 chief and hereditary vassals to various neighboring regions, granting them fiefs of over 10,000 koku or more, thus elevating them to the status of daimyo. Ieyasu aimed to make them a protective shield around the Tokugawa clan.

The strength of the Tokugawa vassal group’s can be traced back to their role as shields for Ieyasu during his hostage period under the Imagawa clan. They were always at the forefront of the battlefield, dedicated to win battles for Ieyasu and valuing their lives for his sake. Through combat, the vassal unity was forged and their bonds deepened. In later years, Ieyasu proudly stated, “My treasure is having around 500 vassals who can stand in for me”. One examples of their unwavering loyalty include Natsume Yoshinobu, who stood in for Ieyasu during the Battle of Mikatagahara, and Torii Suneemon, who escaped from Nagashino Castle during the Shitaragahara Battle, only to return to fight again. Suneemon, who was captured by the Takeda forces and crucified for his loyalty to Ieyasu, died in service of his lord.

Ieyasu’s shock after the defection of Ishikawa Kazumasa

However, there were vassals who did not only act out of loyalty to Ieyasu. One such example is Ishikawa Kazumasa, who held a prominent position among the hereditary vassals of Mikawa and was favored by Ieyasu, but defected from his post in Okazaki castle and joined Toyotomi Hideyoshi. This act of betrayal deeply shocked Ieyasu. However, Ishikawa’s actions implanted in the vassals the consciousness that “betrayal is unjust,” which ultimately contributed positively to Ieyasu’s control of his vassal group. Turning a negative into a positive, this reflects the way of life that Ieyasu adhered to.

As a result of the victory in the Battle of Sekigahara, which led to the confiscation and reduction of 90 daimyo families in the Western Army, Ieyasu incorporated a total of 6.22 million koku into his direct domain and distributed it to the commanders of the Eastern Army as rewards for their military achievements. However, in the case of Toyotomi-affiliated daimyo such as Kato Kiyomasa, Fukushima Masanori, and Hosokawa Tadaoki, Ieyasu not only granted them increased territories but also relocated them to the western region of Japan, solidifying the Kanto region with loyal and hereditary vassals. As a result, 68 loyal and hereditary daimyo were created, further strengthening the power of Ieyasu and the Tokugawa family. Additionally, prominent figures such as Ii Naomasa, Honda Tadakatsu, and Sakakibara, who were at the center of military and political affairs, were separated from the Kanto region as a means of controlling powerful outside daimyo.

Placing hereditary vassals from Mikawa province close to shogun Tokugawa Hidetada

Ieyasu, who established the shogunate in Edo in 1603, handed over the shogunate to his son Hidetada two years later allowing him to reside in Edo Castle, while Ieyasu himself lived in Sunpu Castle as “Grand Gosho” or great elder. The authority of the shogun was divided, with Hidetada entrusted with the governance and ruling power, while Ieyasu took charge of organizing the shogunate and ensuring the stability of territories and stipends. Ieyasu was in charge of military command, including the feudal lords and their families, as well as the administration of the fiefs and domains. This was the content of the “dual government” that Ieyasu had planned. Moreover, Hidetada’s direct vassals consisted mainly of the hereditary family members from Mikawa, while the Edo Castle was staffed by elder statesmen. The dual governance policy served as the final touch in Ieyasu’s control over his vassal group, and the results can be observed in the loyalty and unity achieved.

Not only did Ieyasu strengthen the bonds with the hereditary vassals, but he also pursued a policy of deepening ties (Tokugawa-ization) with various daimyo, including not only the hereditary vassals but also the outsiders. One of the strategies employed was the reinforcement of marriage policies. While marriage policies were common among warlords, including Hideyoshi, Ieyasu’s scale and efforts in this regard were particularly extensive.

Ieyasu’s grasp of the people extended not only to the hereditary vassals but also to numerous warlords of the Sengoku period. Among them, Tōdō Takatora, who changed allegiance seven times throughout his lifetime, ended up considering Ieyasu his best lord. Tōdō learned from Ieyasu what methods were best for controlling vassals, resulting in his profound admiration for Ieyasu as an exceptional lord. In a way, Ieyasu’s way of life and charm, so to speak, were the secret of the strength of the Tokugawa vassals’ unity.

Supervised and Written by Emiya Takayuki

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