Yamagata Masakage


Yamagata Clan

Kai Province

Yamagata Masakage

Lifespan:  Eishō 12 (1515) or Kyōroku 2 (1529) to 5/21 of Tenshō 3 (1575)

Other Names:  Obu Genshirō, Saburō Hyōe-no-jō

Rank:  bushō

Clan:  Obu → Yamagata

Lord:  Takeda Shingen → Takeda Katsuyori

Siblings:  Obu Toramasa (or may have been an uncle), Masakage

Children:  Masamitsu, Masahisa, Masatane, Nobutsugu, daughter (wife of Saigusa Masasada), daughter (wife of Aiki Jōrin), daughter (wife of Yokota Korematsu)

Adopted Children: Sadamasa, Tarōemon

Yamagata Masakage served as a bushō during the Sengoku and Azuchi-Momoyama periods.  Masakage was a retainer of the Kai-Takeda clan and a hereditary member of the chief retainers.  In later eras, he was counted among the Four Guardian Kings of the Takeda.

He is known as either the younger brother or nephew of Obu Toramasa, a hereditary chief retainer of the Takeda.

On 10/17 of Eishō 12 (1515), an individual named Genshirō who appeared to be the son of Obu Dōetsu, a retainer of Takeda Nobutora and member of the Obu clan, died in battle against Ōi Nobusato, a kokujin, or provincial landowner, in the Nishi District.  The name Genshirō matches the pseudonym of Masakage, so it is surmised that Genshirō was the father of Toramasa and Masakage.

Masakage first served as an attendant of Takeda Shingen, and then as a messenger and scout on the battlefield.  Masakage first experienced battle in an attack on Ina during the Invasion of Shinano in the era of Takeda Harunobu (later known as Shingen).

In an attack on Kannomine Castle, Masakage served with valor in the vanguard and, in 1522, owing to his contributions during an invasion of Shinano, he was chosen as a samurai general in command of 150 troops.  Thereafter, he performed as a valiant warrior rivaling the prowess of Toramasa so that it was said “wherever Genshirō goes there are no enemies.”

His name first appears in an authenticated account dated 8/2 of Kōji 2 (1556) whereby Masakage, identified as Obu Genshirō, serves as an official to convey a sealed license for an exemption from transit taxes to go to and from the Zenkō Temple in Shinano granted to Mizushina Shūri-no-jō.

In 1563, he adopted the name of Saburō Hyōe-no-jō.  Thereafter, he steadily contributed on the battlefield, becoming a general of 300 soldiers ranking with the group of hereditary chief retainers.

In the seventh month of 1564, he invaded Hida Province, forcing the surrender of the Ema and Miki clans.

In the tenth month of 1565, Shingen’s eldest son, Takeda Yoshinobu, and his mentor, Obu Toramasa, launched a rebellion and, on 10/15, Toramasa was forced to commit seppuku.  This is known as the Yoshinobu Incident.  There is a story that after Masakage became aware that Toramasa (a blood relative) was involved, he notified Shingen.  Owing to this contribution, Masakage took over the battalion of Toramasa adorned in red-colored armor.  From the surname of Obu, he was conferred the surname of Yamagata that had ended in the era of Nobutora and adopted the name of Yamagata Masakage.

As of the eighth month of 1566, he changed his surname.  Masakage and Hara Toratane are said to have been appointed to the elevated role known as ryōshoku in charge of security and the adjudication of disputes arising in the Takeda territory.  These appointments, however, have not been confirmed from primary sources.  Their predecessors in this role were Itagaki Nobukata and Amari Torayasu.  Thereafter, Masakage participated in the battle to capture Minowa Castle during the Invasion of Western Kōzuke, the Invasion of Suruga against the Imagawa clan, and, after the collapse of the alliance between the Takeda and the Hōjō, in the battle against the Gohōjō clan of Sagami Province.  As a close associate of Shingen, Masakage served as an official in the Takeda territory for the issuance of licenses and tax exemptions, deployment orders, governance of shrines and temples, and so forth.  He also served as an intermediary with provincial landowners outside the territory such as the Tōyama clan of Mino, the Ashina clan of Mutsu, and the Mikawa-Tokugawa; the Matsuo-Ogasawara, the Muroga, and the Akasu clans of Shinano; and retainers of the Kai-Takeda such as the Saigusa and the Yokota clans.

In 1569, Masakage was appointed as the chamberlain of Ejiri Castle in Suruga.

In 1571, the Takeda launched a major invasion of Tōtōmi and Mikawa provinces, Masakage subdued the kunishū of Oku-Mikawa including the Okudaira and Suganuma clans known as the Yamaga-sanpōshū.  On 4/28, Masakage crushed the base of Suganuma Sadamitsu at Ōnoda Castle, forcing Sadamitsu to flee.  He then surrounded Yoshida Castle.

In the tenth month of 1572, after Shingen commenced the Western Expedition, Masakage and Akiyama Torashige led a detached unit from Shinano to invade Mikawa.  Provincial landowners from Oku-Mikawa, such as the Suganuma and Okudaira clans obedient to the Takeda, were folded into Masakage’s command so he had these forces take the lead to march via Nagashino Castle in eastern Mikawa toward Hamamatsu.  These forces toppled Kakimoto Castle in the Yana District of Mikawa followed by Idaira Castle in Tōtōmi Province, and then proceeded southward.  After laying the foundation to pressure Hamamatsu Castle, the forces converged with Shingen’s main division.  On 12/22, the Battle of Mikatagahara broke out between the Takeda forces and Tokugawa Ieyasu of Mikawa.  Just as the Yamagata division began to collapse, Takeda Katsuyori came to their rescue.

On 4/12 of Genki 4 (1573), Shingen died in Komaba in the Ina District of Shinano Province.  Before dying, Shingen requested that his death be kept secret for three years and that support be given to Katsuyori.  He further requested that the war banner be planted in Seta.  Thereafter, Masakage, together with Baba Nobuharu, as a mainstay within the clan, supported Takeda Katsuyori.  Relations with Katsuyori, however, waned so Masakage became estranged from Katsuyori.

After Katsuyori succeeded Shingen, on 8/21 of Tenshō 1 (1573), Masakage was ordered to command the rear guard for Nagashino Castle in Mikawa.

In 1574, in a battle for Akechi Castle in the Kani District eastern Mino during an invasion by Katsuyori, Masakage made use of the mountainous terrain with a detached division of 6,000 soldiers to repel the main division of Oda Nobunaga with 30,000 men who rushed to the aid of the defenders.  The Yamagata division pushed back the Oda army approximately sixteen kilometers, killing nine of the sixteen mounted soldiers protecting Nobunaga with the other seven fleeing which pushed Nobunaga to the brink.

Battle of Nagashino

In the fifth month of 1575, at the Battle of Nagashino, Masakage, along with Naitō Masahide, Baba Nobuharu, and Hara Masatane, recommended that the forces withdraw, but Katsuyori and his close associates, Nagasaka Mitsukata and Atobe Katsusuke advocated for a final showdown whereupon Katsuyori decided to engage in battle.

On 5/21, in the final showdown at Shitaragahara, Masakage, together with Masahide and Masatane formed the nucleus of the left wing of the Takeda army.  Masakage led 300 soldiers, including those from the Asahina of Suruga, the Matsuo-Ogasawara of Shinano, the Aiki-Yoda cla, the Ōkuma clan, the Damine-Suganuma clan, the Nagashino-Suganuma clan, the Miura clan of Tōtōmi and the Haramiishi clan.

The offensive by the Takeda force began at 11:00 AM when the left wing under the command of Masakage charged the Tokugawa army.  According to the authenticated biography of Oda Nobunaga known as the Shinchō-kōki, the Yamagata forces served in the first line, but were defeated and, around 2:00 PM, retreated.  Takeda commanders including Masakage and Sanada Nobutsuna were killed at the height of the retreat.  Masakage was forty-seven years old.  According to records at the Seikei monastery on Mount Kōya, he died around 2:00 PM.

A painting of the Battle of Nagashino on a folding screen depicts a retainer named Shimura Matazaemon (Sadamitsu) carrying the head of Masakage who was killed in battle so that it would not be taken by the enemy forces.


In the authenticated biography of Oda Nobunaga known as the Shinchō-kōki, Masakage appears at the top of the list of bushō who took enemy heads at the Battle of Nagashino.  This reflects how widely he was known among enemy forces and his leadership status among senior retainers of the Takeda family.  He was counted among the Four Guardian Kings of the Takeda as well as one of the Twenty-Four Generals of the Takeda.

The Yamagata division wore red-colored armor so were known as the “Red Corps” feared by many daimyō.  Simply observing the red corps would make even courageous fighters shudder.  Owing to the intrepid reputation of the Yamagata division, the Red Corps became a symbol of the most powerful force, exerting a significant influence upon other daimyō.  After the death of Masakage, Ii Naomasa (a senior retainer of Tokugawa Ieyasu) and Sanada Nobushige (the second son of Sanada Masayuki) adopted the red attire which also served to magnify their presence.

Masakage was a valorous bushō, but he did not have an impressive countenance.  He was short in stature (130 to 140 cm), lightweight, cutting a slim figure and with a harelip, called an ugly man.  One account, however, depicts Masakage as follows: “…a small man with only 12 to 15 centimeters between his head and waist, uncoordinated but intelligent and loud like thunder.  Even among Shingen’s retainers, he was a right-hand man.  Opposing samurai generals were fearful of the small man’s presence.”

Obu Heibu is often considered Masakage’s younger brother, but owing to the age difference, may have been his nephew.  This is based on genealogical charts in the historical accounts of the Hagi (Chōshū) domain transmitted to the Mōri clan, the sengoku daimyō of Aki Province.  According to this source, Masakage’s father was Yamagata Shigeaki, the lord of Mibu Castle and a kokujin in Aki serving the Aki-Takeda clan.  His older brother was Yamagata Shigefusa.  Masakage’s mother was the older sister of Obu Heibu and, at around eleven years of age, Masakage absconded and headed to Kai Province to rely upon his uncle in the family where Masakage’s sister was married.  However, it  has not been confirmed from primary sources that Masakage originated from the western provinces.

Masakage’s eldest daughter wed Saigusa Masasada, a retainer of the Kai-Takeda and general of the ashigaru, or lightly armored foot soldiers.  Masasada, who was counted among the Twenty-Four Generals of the Takeda, adopted the surname of Yamagata.  Other son-in-laws included Aiki Ichibei who led the reserves for the Yamagata division and Yokota Tadatoshi who became a hatamoto, or direct retainer, of the Edo bakufu in the Edo period.


During the Battle of Kawanakajima, Masakage engaged in a one-on-one duel against a fierce bushō in the Uesugi army named Kojima Yatarō.  At the height of this duel, Masakage noticed that Takeda Yoshinubu (the eldest son and designated heir of Takeda Shingen) was in a precarious situation, so he said to Yatarō that he would like to delay the contest to save his lord to which Yatarō readily agreed.  Masakage praised Yatarō as a courageous soldier who not only appeared impressive but was also personable.

Ichijō Nobutatsu, the younger brother of Shingen of a different mother, inquired of Masakage as to why the Yamagata division was so formidable, to which Masakage replied:  “While training is important, the most critical factor is the state of mind with respect to battle.  We make meticulous plans before heading into battle each time as though it was our first, and even if we think we can win, we do not fight until we are certain we can do so.”

During an invasion of Hida Province, a monkey appeared and led the exhausted soldiers with low morale to an onsen, or natural hot springs, where the men could recover from their weariness.  This later became the Hirayu Onsen.

Nobutsugu’s descendants currently operate a traditional travel lodge known as the Yamagata-kan in Mitomikawaura in Yamanashi Prefecture.