Sanada Masayuki (1547 – July 13, 1611) was a daimyo and prominent lord of Japan's Sengoku period. Head of the Sanada clan from Shinano Province, he served the powerful Takeda clan of Kai Province alongside his father and brothers during Takeda Shingen’s leadership. Following the Takeda clan's decline, Masayuki took charge of the Sanada, and despite limited resources, he established his clan as an independent power under the Toyotomi regime by navigating alliances with dominant clans such as the Tokugawa, Hojo, and Uesugi. Renowned as one of his era's greatest strategists, Masayuki achieved notable victories against the Tokugawa forces in the Battle of Kami River and the Siege of Ueda.
Born the third son of Sanada Yukitaka in 1547, Masayuki was initially ineligible to inherit his father's position due to his elder brothers, Nobutsuna and Masateru. At the age of seven, he was sent as a hostage to the Takeda headquarters in Kai Province, where he became part of the Okukinjushu—a select group of trusted young attendants close to Takeda Shingen. According to the Koyo Gunkan, Shingen quickly recognized Masayuki’s talents, which rivaled those of his father, Yukitaka, and included him among his Twenty-Four Generals, along with Yukitaka and his brothers.
In 1558, he was adopted by the Muto family, a branch of the Oi clan and relatives of Shingen’s mother, taking on the name Muto Kihei.
Service under the Takeda Clan
Around 1564, Sanada Masayuki married Yamanote-dono, the daughter of Uda Yoritada, a local lord from Totomi Province. While serving the Takeda clan, Masayuki participated in several pivotal battles, including the Fourth Battle of Kawanakajima in 1561 and the Battle of Mimasetoge in 1569. In 1572, he joined Takeda Shingen in a campaign toward Kyoto against the Oda and Tokugawa clans, participating in the Battle of Mikatagahara (1573).
Following Shingen’s death in 1573, Masayuki continued to serve Shingen’s successor, Takeda Katsuyori. The next year, Masayuki’s father, Yukitaka, passed away, leaving Masayuki's older brother Nobutsuna as clan head. However, both Nobutsuna and his other brother Masateru were killed in the disastrous Battle of Nagashino (1575) against the Oda. With his brothers gone, Masayuki claimed leadership of the Sanada clan, a position Takeda Katsuyori endorsed, reportedly with the support of Kosaka Masanobu, a Takeda chief retainer.
In 1579, an alliance was forged between the Takeda and Uesugi clans following Uesugi Kenshin’s death. Under Katsuyori’s orders, Masayuki invaded western Kozuke, a Hojo-controlled area, capturing Numata Castle and securing it for the Takeda. In 1581, he was appointed Awa-no-kami (Governor of Awa) and oversaw the construction of Shinpu Castle. When Numata Kageyoshi, the former lord of Numata Castle, attempted to reclaim it, Masayuki thwarted him with a successful assassination plot.
In April 1582, combined forces from the Oda and Tokugawa clans launched an invasion into Takeda territory. Masayuki proposed that Katsuyori seek refuge in the Sanada domain at Iwabitsu Castle, but Katsuyori chose to flee to Iwadono Castle, where he was betrayed and met his end at Tenmokuzan. After the Takeda clan’s collapse, Masayuki submitted to Oda Nobunaga, who allowed him to retain most of his lands under Takigawa Kazumasu’s command, though he had to cede Numata Castle to Takigawa’s relative.
The Tensho-Jingo Conflict
Following Nobunaga’s death at the Incident at Honno-ji on June 21, 1582, chaos erupted as Oda control over former Takeda territories weakened. Amid this turmoil, Tokugawa Ieyasu moved into Kai and Shinano Provinces, supported by senior Oda vassals, aiming to solidify his power. However, the Uesugi and Hojo clans also laid claim to these regions, where remnants of former Takeda-aligned clans held sway. The resulting power struggle between the Tokugawa, Uesugi, and Hojo clans is known as the Tensho-Jingo Conflict.
On June 13, the Hojo clan captured Iwadono Castle in Tsuru District and enlisted local magnate Watanabe Shozaemon to support their conquest. Masayuki, initially aligned with the Uesugi, shifted his allegiance to the Hojo on July 9 and surrendered to Hojo Ujinao. Meanwhile, on July 5, Takigawa Kazumasu suffered a severe defeat against the Hojo at the Battle of Kannagawa. Masayuki escorted Kazumasu’s remaining forces back through Suwa, then seized the opportunity to retake Numata Castle with the help of his uncle Yazawa Yoritsuna and installed his son, Nobuyuki, as the commander of Iwabitsu Castle, strengthening Sanada presence in eastern Kozuke.
In July, Uesugi Kagekatsu invaded northern Shinano, leading Masayuki to ally temporarily with the Uesugi before switching back to the Hojo. Both armies met at Kawanakajima on July 30 but avoided direct combat when the Hojo forces redirected their efforts south to Kai Province, which the Tokugawa were simultaneously invading. Meanwhile, a rebellion by Shibata Shigeie, a Uesugi retainer, forced the Uesugi forces to retreat from northern Shinano.
On October 19, Masayuki abruptly changed his allegiance to the Tokugawa, attacking Nezu Masatsuna, a Hojo lieutenant, and coordinating with Yoda Nobushige to resist Hojo forces near Komoro, following orders from Ieyasu. The Hojo, learning of Masayuki’s defection, attempted to capture Numata Castle, but Masayuki successfully defended his position.
Conflict with the Tokugawa
In 1583, Sanada Masayuki began constructing Ueda Castle and its surrounding town, establishing it as the Sanada clan’s primary stronghold. In 1584, while Tokugawa Ieyasu marched west to engage Hashiba Hideyoshi in the Battle of Komaki and Nagakute, Masayuki remained in northern Shinano to monitor the Uesugi clan. He used this opportunity to consolidate power in the region by subjugating nearby landowners. When Ieyasu made peace with Hideyoshi later that year, he faced pressure from Hojo Ujinao to transfer Numata Castle to the Hojo per their treaty.
By April 1585, Ieyasu’s forces had advanced into Kai Province to pressure Masayuki to relinquish Numata Castle. Unwilling to part with the hard-won territory, Masayuki severed ties with Ieyasu and allied with Hideyoshi by sending his second son, Nobushige, as a hostage to the Uesugi clan. In retaliation, Ieyasu’s forces attacked the Sanada domain in northern Shinano, besieging Ueda Castle with 7,000 soldiers. Masayuki, with only 1,200 defenders, inflicted severe losses on the Tokugawa forces in what became known as the First Battle of Ueda Castle, significantly enhancing his reputation as a military strategist. Meanwhile, Hojo forces also attacked Numata Castle but were repelled.
In 1586, Ieyasu, now reconciled with Hideyoshi, was given permission to attack Masayuki due to the latter’s failure to send family hostages to signify his submission. Masayuki quickly requested mediation from Uesugi Kagekatsu, offering to formally surrender to the Toyotomi clan. Hideyoshi ordered Ieyasu to withdraw, and Masayuki later traveled to Kyoto to pledge allegiance directly to Hideyoshi. After his victory over the Tokugawa, Masayuki became a vassal to Hideyoshi, sending his son Nobushige as a hostage to Osaka. That same year, Hojo forces made another unsuccessful attempt to capture Numata Castle. In 1589, Hideyoshi mediated the longstanding dispute between the Sanada and Hojo clans over Numata, awarding Numata Castle to the Hojo in exchange for land in southern Shinano for the Sanada.
Despite the settlement, tensions resurfaced when Hojo retainer Inomata Kuninori attacked Nagurumi Castle, violating Hideyoshi’s prohibition against private conflicts among daimyos. This incident contributed to Hideyoshi’s decision to launch the Siege of Odawara in 1590, leading to the eventual fall of the Hojo clan.
Following Hideyoshi’s death in 1598, Masayuki sided with Ishida Mitsunari during the Battle of Sekigahara. He sent his eldest son, Nobuyuki, to join the eastern forces, while he and his younger son, Nobushige, fought for the western alliance, a strategic move to secure the Sanada clan’s future. At Ueda Castle, Masayuki’s 2,000 soldiers held off Tokugawa Hidetada’s 38,000-strong army in the Second Battle of Ueda Castle, delaying them enough to prevent their timely arrival at Sekigahara. Although Mitsunari’s side ultimately lost, Masayuki’s foresight saved his family; rather than being executed, he and Nobushige were exiled to Kudoyama in Kii Province, thanks to Nobuyuki’s loyalty to the Tokugawa.
Exile and Legacy
In exile, Masayuki received support from Nobuyuki and from various local sources, including the Kii Domain’s lord Asano Nagaakira. Historical records indicate that Masayuki’s financial struggles were alleviated through aid from nearby temples and nobles, including an annual grant of 50 koku from Asano Nagaakira and donations from Shinkoji Temple.
Though he never amassed vast territories like other daimyos, Masayuki is remembered as a brilliant strategist adept at navigating the turbulent political landscape of his time. While Toyotomi Hideyoshi reportedly viewed Masayuki as untrustworthy due to his shifting allegiances, these very maneuvers ensured the Sanada clan’s survival. Since the Edo period, Masayuki’s reputation has been celebrated, recognizing his resilience and strategic prowess in preserving his family’s legacy amidst Japan’s warring clans.
See also
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Sakakibara Yasumasa
Yasumasa was the second son of Sakakibara Nagamasa and was born in Ueno in Mikawa Province. From a young age, he began serving Tokugawa Ieyasu and eventually rose to the position of one of his most trusted generals. His wife was the daughter of Osuga Yasutaka. Ieyasu first noticed the young Yasumasa during the suppression of the Ikkō-ikki uprising in Mikawa in 1564. Thanks to his demonstrated abilities, Yasumasa was granted the privilege of using the character “yasu”—the second character of Ieyasu’s own name—in his own. Although he was the second child in his family, he became his father’s heir, though the exact reasons for this remain unknown.
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Sakai Tadatsugu
Tadatsugu was one of the most renowned generals serving Tokugawa Ieyasu. After Ieyasu broke ties with the Imagawa clan, Tadatsugu—an ardent supporter of this decision—was granted command of Yoshida Castle in 1565, which controlled the coastal road from Tōtomi to Mikawa. During the Battle of Mikatagahara in 1573, he held the right flank of the Tokugawa forces even when the troops sent by Oda fled under the assault of the Takeda army. In the Battle of Nagashino in 1575, he personally requested permission to carry out a night attack on the Takeda camp, which he executed brilliantly together with Kanamori Nagachika.
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Ryuzoji Takanobu
Takanobu was the eldest son of Ryūzōji Takaie and the great-grandson of Ryūzōji Iekane. His father was killed by a man named Baba Yoritiku in 1544. At a young age, Takanobu took Buddhist vows and received the monastic name Engetsu. However, around the age of eighteen, he returned to secular life, and in 1548, after the death of Ryūzōji Tanehide, he became the head of both branches of the Ryūzōji family.
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Ouchi Yoshihiro
Ōuchi Yoshihiro was the second son of Ōuchi Hiroyo, who headed the Ōuchi clan in the western part of Honshu. In 1363, Shogun Ashikaga Yoshimitsu confirmed the Ōuchi family in the position of shugo of Suō and Nagato Provinces. In his youth, Yoshihiro assisted his father in strengthening the influence of the Northern Court on the island of Kyushu — they served under Imagawa Ryōsun, who had been tasked with subjugating the nine provinces of Kyushu.
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Ouchi Yoshioki
Ouchi Yoshioki, the ruler of the provinces of Suo, Nagato, and Iwami, was one of the most capable military commanders and politicians of the late 15th and early 16th centuries. The son of Ouchi Masahiro, he governed from his residence in Yamaguchi in the province of Suo. In 1499, Yoshioki gave refuge to Shogun Ashikaga Yoshitane, who had been driven out of Kyoto by Hosokawa Masamoto. Shogun Yoshizumi, Masamoto’s protégé, ordered the lords of Kyushu to unite their forces against Yoshioki; however, they did not dare to do so, fearing the power of a man who by that time controlled six provinces. Having gathered a substantial army, Yoshioki marched from his native Suo toward Kyoto in order to restore Shogun Yoshitane to power.
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Otomo Sorin
Ōtomo Yoshishige came from a noble lineage, being the eldest son of Ōtomo Yoshiaki, the ruler of Funai Province. The roots of the Ōtomo family traced back to Fujiwara Hidesato, the adopted son of Nakahara Chikayoshi. Fujiwara served Minamoto Yoritomo during the Genpei War and took part in battles in Mutsu Province in 1189. In 1193, he was appointed shugo of Buzen and Bungo Provinces, after which he adopted a new surname—Ōtomo.
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Okudaira Sadamasa
Sadamasa was the son of Okudaira Sadayoshi and took part in several battles under Tokugawa Ieyasu, distinguishing himself in the Battle of Anegawa in 1570, where he took two heads. Around 1572 he was forced to enter the service of the Takeda clan, but after the death of Takeda Shingen in 1573 he returned to Tokugawa, leaving Tsukude Castle together with his men. As a result of this defection, Takeda Katsuyori ordered the execution of Sadamasa’s wife and brother, who were being held as hostages.
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Okubo Tadatika
Tadatika, the son of Okubo Tadayō, entered the service of Tokugawa Ieyasu at the age of eleven, and took his first head in battle when he was sixteen. After the establishment of the Tokugawa shogunate, he was appointed as a rōjū — a senior bakufu official — and was regarded as one of Ieyasu’s most trusted advisors, alongside Honda Masanobu. He is also known for his military chronicle Mikawa Monogatari, which describes Ieyasu’s rise to power and the early years of the Tokugawa shogunate.
