Imagawa Yoshitada served as a bushō and shugo daimyō during the late-Muromachi and Sengoku periods.  He was the eighth head of the Imagawa clan and military governor of Suruga Province.  Yoshitada was the grandfather of Imagawa Yoshimoto.

In 1441, during the Kakitsu Disturbance, Yoshitada served on behalf of his father, Imagawa Noritada, to lead 1,000 soldiers to Owari Province.

In 1454, during the Kyōtoku War, Yoshitada deployed on behalf of his father who was ordered by the Muromachi bakufu to eliminate Ashikaga Shigeuji, the Kamakura kubō.

For his contributions to capture Kamakura, Yoshitada received a letter of commendation from Ashikaga Yoshimasa, the eighth shōgun of the Muromachi bakufu.  Around this time, he attended his coming-of-age ceremony and was conferred one of the characters from the name of Yoshimasa along with one of the characters from the name of his father, adopting the name of Yoshitada.

In 1461, after his father became critically ill, Yoshitada inherited the position as the military governor of Suruga.  After becoming the head of the clan, Yoshitada received orders from Ashikaga Yoshimasa to assist Ashikaga Masatomo, the Horigoe kubō.  In 1466, he was ordered along with Takeda Nobumasa of Kai Province to subdue Ashikaga Shigeuji who had moved from Kamakura to Koga.

Owing to the former achievements of Imagawa Sadayo from the early Muromachi period, the Imagawa clan held the position of military governors of Tōtōmi outside of their home base of Suruga Province until 1419, after which the position was acquired by the Shiba clan.

In 1459, Imagawa Norimasa of the Tōtōmi-Imagawa clan served as the nucleus of the Chūen-ikki.  This began as a local uprising and escalated into battles against the Shiba and Kano clans.  In the end, the uprising was suppressed by the Shiba (who were serving as military governors of Tōtōmi).  After the demise of Norimasa, perhaps because his landholdings including Horigoe were taken away by Kano Kunai-Shōyū (the deputy military governor), on 7/26 of Kanshō 6 (1465), Kunai-Shōyū’s position as the deputy military governor was legitimized after he obtained authorization from the bakufu as the local governor of these landholdings.  As a result, after the ouster of Imagawa Sadanobu from Mitsuke Castle, Yoshitada offered him protection in Suruga, further heightening tensions between the Imagawa and Shiba clans.

Ōnin-Bunmei War and expedition to Tōtōmi Province

In 1467, upon the outbreak of the Ōnin-Bunmei War and after consulting with Masatomo, Yoshitada led 1,000 soldiers on a march to the capital.  Yamana Sōzen made efforts to persuade him to join the Western Army but based on the original premise of going to Kyōto to guard the shōgun, he entered the palace of the shōgun (known as the hana no gosho) occupied by the Eastern Army and joined their forces.  This may have owed, in part, to the ongoing conflict that he had with Shiba Yoshikado, the military governor of Tōtōmi, who was in the Western Army.

There are various theories concerning Yoshitada’s wife, Kitagawa-dono, and her younger brother, Ise Sōzui (later known as Ise (Shinkurō) Moritoki and then Hōjō Sōun).  Her father was Ise Morisada and mother was the daughter of Ise Sadakuni.  She was previously considered to have been Yoshitada’s consort from around the time that Shinkurō was a lowly rōnin, or wandering samurai.  Based on more recent research, Shinkurō is understood to be Ise Moritoki, a retainer of the shōgun from the Bitchū-Ise clan who were members of the prominent Ise clan (who, in turn, served as directors of the mandokoro, the organ with authority to adjudicate claims over land or finances for the Muromachi bakufu).  While visiting Kyōto, Yoshitada frequently visited Ise Sadachika  while Kitagawa-dono’s father, Morisada, served as a member of the mōshitsugishū, or intermediaries for communications between the shōgun and the Imagawa family.  Through this connection, Kitagawa-dono wed Yoshitada around 1467.  Moreover, owing to the social status of the Kitagawa family, she is regarded to have been his formal wife.  In 1473, Kitagawa-dono bore a lineal heir, Tatsuōmaru (later known as Imagawa Ujichika) at the Imagawa mansion in Sunpu.

In 1468, upon demand of Hosokawa Katsumoto, Yoshitada returned to Suruga to stir chaos in neighboring Tōtōmi – a province in the Tōkai region held by Shiba Yoshikado.  He then aimed to advance into Tōtōmi and battled against the Shiba clan and kokujin in Tōtōmi.

In 1473, Yoshitada, upon orders of the shōgun, deployed to Mikawa Province to support Hosokawa Shigeyuki, the military governor of Mikawa affiliated with the Eastern Army who was under attack from Saitō Myōjun from the family of the deputy military governors of Mino Province.  Yoshikado, however, came into conflict with Shiba Yoshisuke (later known as Shiba Yoshihiro), the military governor of Owari Province of the same Eastern Army (who, after the outbreak of the war, was appointed as the military governor of Tōtōmi in lieu of Shiba Yoshikado of the Western Army) over landholdings allocated by the shōgun for the cultivation of food provisions for the military.  Yoshikado also stood in opposition to the Komi and Kano clans, kokujin in Tōtōmi, who served as lower-ranking officials of Kira Yoshizane of Mikawa Province.  With the support of another servant of the Kira clan, Inoo Nagatsura, he decimated these kokujin.  As a result, despite being in the same Eastern Army, Yoshikado came into conflict with Shiba Yoshisuke and Hosokawa Shigeyuki.

In 1475, Kai Toshimitsu, a senior retainer of Yoshikado who earlier defected from the Western Army to the Eastern Army, was appointed by Yoshimasa as the deputy military governor of Tōtōmi.  Although Yoshikado and Toshimitsu were both affiliated with the Eastern Army, their relationship deteriorated owing to Yoshikado’s desire to remove the influence of the Shiba clan from Tōtōmi (irrespective of Yoshisuke and Yoshikado).  The situation in Tōtōmi then fell into disarray.  Toshimitsu and Yoshisuke went from the capital to Tōtōmi and increased the military pressure.  Yoshikado also deployed to Tōtōmi and fought against the kokujin who were aligned with Yoshisuke.

Attacks in Tōtōmi and demise

In the fourth month of 1476, Yoshitada, attacked kunishū, or provincial landowners, in Tōtōmi Province including Yokochi Shirōbei at Kinsu (Yokochi) Castle and Katsumata Suri-no-suke at Katsumata Castle.  While returning to Suruga, at the Battle of Shiokaizaka, Yoshitada was attacked and killed by remnants of these clans after being struck by a stray arrow while commanding troops from atop his horse.  

A historical account of the Imagawa family regards the Yokochi and Katsumata clans as rebels who betrayed the bakufu.  Given that Shiba Yoshisuke who colluded with both clans was appointed as a military governor, there is a view that the Yokochi and Katsumata clans were simply following orders from the bakufu and military governors whereas Yoshitada, by attacking these clans, acted in a manner that violated the authority of the bakufu.

Shiokaizaka was in the opposite direction from the route to return from Kinsu Castle to Sunpu so there is a theory that after suffering a defeat at Kinsu Castle, Yoshitada was killed while seeking to flee for safety to Shinya Castle (aligned with the Imagawa) to the south of Shiokaizaka.  The anniversary of Yoshitada’s death is subject to various theories.  According to one account, Ōta Dōkan deployed in the third month to join forces with Oshika Norimitsu so the anniversary appears to be on 2/19 as noted in a historical account of the Imagawa family.

Succession struggle

At the time of the unexpected death of Yoshitada, his lineal heir, Tatsuōmaru, was only around five years old.  Despite his young age, Tatsuōmaru and his mother, Kitagawa-dono, were at risk of being killed owing to their familial status as the wife and son of a traitor.  Within the Imagawa clan, Yoshitada’s younger cousin, Oshika Norimitsu, backed by retainers including the Miura and Asahina clans, asserted that he should become the successor to the clan, triggering a succession struggle.  This gave rise to concerns of intervention by Norimitsu’s maternal relatives, the Ōgigayatsu-Uesugi family (Ōta Dōkan, the head of house affairs), who cooperated with the bakufu (the Eastern Army) during the Kyōtoku War.  It appears that Norimitsu and Dōkan considered eliminating Tatsuōmaru.

The faction supporting Tatsuōmaru engaged in a series of battles against the faction backing Norimitsu.  Meanwhile, the Yokochi and Katsumata clans who were responsible for the death in battle of Yoshitada colluded with the Shiba clan and served Shiba Yoshisuke, the military governor of Tōtōmi formally appointed by the bakufu. 

By obstructing them, Yoshitada was viewed as a rebel by the bakufu so rather than have his orphan, Tatsuōmaru, succeed to the headship of the clan, there was a possibility that he would be eliminated as a family member of a rebel.  Consequently, Kitagawa-dono took Tatsuōmaru and fled for the protection of Hasegawa Masanobu, a wealthy landowner serving as the lord of Kogawa Castle.

Although the bakufu was not contemplating the elimination of Tatsuōmaru as the lineal heir to the Imagawa family, based on the circumstances of Yoshitada’s demise, a need arose for the bakufu to protect him.  Therefore, to mediate the dispute within the Imagawa clan (and to protect Tatsuōmaru), the bakufu sent Ise Moritoki (a member of the mōshitsugishū, or intermediaries between the shōgun and daimyō families) from the capital to Suruga.  Moritoki was the younger brother of Kitagawa-dono and the son of Ise Morisada who was involved for many years in issues in Suruga and Tōtōmi.  This strengthened bonds between Moritoki and the Imagawa clan, serving as a catalyst for the advance by Moritoki into the Kantō and the birth of the Gohōjō (or Later Hōjō) clan.

Continuing conflict in Tōtōmi

The Kira clan, along with the Shibukawa and Ishibashi clans, were members of the goikkashū – high-ranking families within the Muromachi bakufu on a par with the deputy shōgun.  In the Kamakura period, the Imagawa clan was founded by Imagawa Kuniuji, the second son of Kira Nagauji.  As such, the Imagawa descended from the main branch of the Kira.  In the era of Yoshitada, the Mikawa-Kira held territory in Tōtōmi including the Hamamatsu manor.  With respect to conflict between the Imagawa and Shiba clans, the Kira endeavored to remain neutral but, among those serving the Kira, the Komi and Kano clans resisted Yoshitada and were decimated.  Inoo Nagatsura, the head of the Inoo clan, acted in concert with Yoshitada but, along with Yoshitada, was killed in battle.  As a result, the band of retainers of the Kira clan in Tōtōmi split between factions supporting the Imagawa and Shiba clans respectively and this became a source of continuing conflict between these clans in Tōtōmi.

In 1508, Yoshitada’s son, Ujichika, invaded Tōtōmi again.  After he acquired the role as military governor of Tōtōmi, the Kira sought to protect the Hamamatsu manor by having the Inoo clan (under the Imagawa) serve as their local governors.  The Ōkōchi clan (under the Shiba) continued to resist the Imagawa, capturing the main base of the Inoo at Hikuma Castle and receiving Shiba Yoshitatsu who aimed for a revival in Tōtōmi.  In 1517, Ujichika recaptured Hikuma Castle and destroyed the Ōkōchi and Komi clans.  During this period, while the Kira did not suppress the Ōkōchi, they did not actively support the Inoo either.  Instead, it appears they responded flexibly to secure the governance of their territory in Tōtōmi during the conflict between the Imagawa and Shiba clans.  In the end, Shiba Yoshitatsu was apprehended and sent to his home province of Owari while Inoo Katatsura, serving as the local governor of the Hamamatsu manor, affiliated with the Imagawa.