Lifespan: Tenbun 6 (1537) to 5/21 of Tenshō 3 (1575)
Other Names: Kageyu-zaemon-no-jō, Yamagata Zenemon
Clan: Ishihara → Saigusa
Lord: Takeda Shingen → Takeda Katsuyori
Father: Saigusa Torayoshi
Siblings: Masasada, Masatsugu, Moriyoshi, Masayoshi, Morimitsu
Wife: [Formal] Daughter of Yamagata Masakage (?)
Saigusa Masasada served as a bushō during the Sengoku period. Masasada was a retainer of the Kai-Takeda clan serving as a general of the ashigaru, or foot soldiers. He is counted among the Twenty-Four Generals of the Takeda.
In 1537, Masasada was born as the eldest son of Saigusa Torayoshi. His father adopted the name of Saigusa Uemon-no-jō and served as a magistrate for the Takeda family. During the Sengoku period, the Saigusa were under the guardianship of Yamagata Masakage, a hereditary retainer of the Takeda.
Masasada was the lineal heir of Torayoshi and initially engaged as a servant for Takeda Shingen. After recognizing his abilities, Shingen promoted Masasada to eventually become a general of the foot soldiers. According to another account, Masasada originated from the same Yamagata clan as Masakage and was adopted by the Saigusa clan, but, in another account, he is identified as the husband of Masakage’s daughter and adopted the name of Yamagata Zenemon-no-jō. From around 1568, he adopted the name of Yamagata Kageyuzaemon-no-jō and commanded 30 mounted soldiers and 70 foot soldiers.
In the Kōji era (1555 to 1558), he angered Shingen and was temporarily confined. He first appears in records in connection with the Battle of Kawanakajima in the third month of 1561. Based on his activities in Shinano, he was granted a fief. In 1563, he was ordered to raise and serve as the guardian for the orphan of his uncle, Saigusa Morinao. in the eighth month of 1569, he served as an official representative of the Takeda in the Shiogo township of Kai so is surmised to have been pardoned around this time.
Later, he served as an official of the Takeda for lands under the direct jurisdiction of the Muromachi bakufu. According to records, Shingen hesitated to grant Masasada an increase to his fief, substantiating stories that Masasada had upset Shingen. Writings from Shingen reveal his emotional side in rebukes of Masasada. Meanwhile, it is noted that Masasada did receive increases to his holdings, reflecting the affinity between Shingen and Masasada.
In the tenth month of 1565, an assassination plot by Shingen’s eldest son, Takeda Yoshinobu, was discovered in an event known as the Yoshinobu Incident. In the eighth month of 1566, the retainers of the Takeda presented written oaths of loyalty to Shingen at the Ikushima-Tarushima Shrine in Shinano Province. Masasada’s name appears along with Nagasaka Masakuni (Gengorō), Yajima Yoshifusa, Satō Minbu-no-shōyū, and others. A year later, in the eighth month of 1567, the Takeda family collected written oaths, during which Masasada submitted an oath again. There is a possibility that Masasada had a close relationship with Yoshinobu.
In 1568, during the Invasion of Suruga by the Takeda army against the territory of the Imagawa, Masasada’s father, Torayoshi, was assigned to oversee Tanaka Castle in Suruga. Shingen relied upon Masasada similar to other of his close associates including Sanada Masayuki and Sone Masatada. During the assault on Hanazawa Castle, Masasada served in the first line of spear fighters and received a written commendation for his contributions. There is a story that he received an invaluable Yoshimitsu sword from Yamagata Masakage. Records of the Takeda battle formations from 1568 indicate that he led the archer battalion.
After the demise of Shingen, Masasada continued to serve the Takeda family in the era of Takeda Katsuyori. In 1575, at the Battle of Nagashino, Masasada was assigned to a detached unit to defend the fortress on Mount Tobinosu from which to observe Nagashino Castle commanded by Kawakubo Nobuzane (the younger half-brother of Shingen from a different mother) so he was separated from the main battlefield. Masasada, along with his younger brothers, was responsible for an outpost constructed in the foothills of Mount Tobinosu called Uba-ga-futokoro. Early in the morning on 5/21, he incurred an attack by a detached unit of Oda and Tokugawa soldiers led by Sakai Tadatsugu sent upon orders of Oda Nobunaga.
To avoid detection by the Takeda forces defending the fortresses, the battalion engaged in the surprise attack approached from behind along a ridge line on the mountainside with the intent of eliminating five enemy fortresses. Among these sites, Uba-ga-futokoro defended by Masasada was the only one not set-up on top of the mountain or on a ridge line, causing delay in detecting an enemy attack. Honda Hirotaka, the lieutenant general, led the forces to attack the defenders at Uba-ga-futokoro from an elevated position. Despite having inferior numbers, Masasada and the other defenders fought valiantly, but gradually lost ground and were overwhelmed after Matsudaira Kiyomune brought reinforcements to the side of the attacking forces after subduing Kimi-ga-fushido fortress nearby. Masasada, along with his younger brothers, Genzaemon Moriyoshi and Jintarō Morimitsu, was killed in action.
There is a gravestone for the Saigusa brothers in the environs of Ubafutokoro where Masasada was killed.
Descendants and ancestors
Masasada’s eldest son and heir, Moriyoshi, was an infant at the time of Masasada’s demise so his uncle, Masayoshi, served as a proxy for Moriyoshi. Masasada’s father, Torayoshi, survived until after the end of the Takeda clan, and, after the Tenshō Jingo Conflict, served the Tokugawa clan in their governance of Kai. After becoming a retainer of the Tokugawa, Masayoshi succeeded to the headship of the Saigusa clan while Moriyoshi started a cadet family. In 1698, descendants of Moriyoshi were reassigned to Ōmi Province and became hatamoto, or direct retainers of the Tokugawa family. This lineage ended in the Meiji period. Family archives from the Morikuni Shrine in the town of Kitasuda in the city of Higashi-Ōmi in Shiga Prefecture and entrusted to a local museum.
In ancient times, the Saigusa clan served as members of the provincial governorate in Kai wielding influence in the eastern portions of the Kōfu Basin. By the late Heian period, this clan is surmised to have ended prior to settlement by the Kai-Genji. In the middle ages, the lineage of the Saigusa drew from Saigusa Morikuni who founded the Daizen Temple on Mount Kashio.
Descendants of Masasada serving as hatamoto, or retainers of the Edo bakufu, traced their distant ancestors from the Sengoku period to the Saigusa who were a gōzoku, or wealthy family, in ancient times. In a historical account of Kai compiled in the late Edo period, the Saigusa were revived by Ishihara Moritsuna, the second son of Ishihara Moritane, an illegitimate branch of the clan established during the era of Takeda Nobutora.
The genealogical relationships between the Saigusa of the Sengoku period and the Saigusa who were a gōzoku from ancient times are not certain. There are documents regarding the lineage of the Saigusa who served as retainers of the Takeda in the Muromachi and Sengoku periods and those of the Kashio-Daizen Temple. The lineage of the Saigusa serving as retainers of the Takeda is traced to the Saigusa who were a gōzoku. Meanwhile, it is noted that there was value to adopting the surname of Yamagata who were the guardians of the Saigusa in the Takeda family during the Sengoku period.
Based on historical records,”yoshi” was regarded as the distinctive character used in the names of those belonging to the Saigusa clan, but in military chronicles compiled in later eras, “mori” was regarded as the distinctive character used in the names of those belonging to the Saigusa clan, while Masasada’s real name is “Moritomo.” This reflects the lineage of Saigusa Morikuni. In premodern times after the end of the Takeda clan, it is surmised there was greater value to emphasize the lineage of the Saigusa clan from ancient Kai.