Saitō Tatsuoki


Saitō Clan

Mino Province

Saitō Tatsuoki

Lifespan:  Tenbun 17 (1548) to 8/14 of Tenshō 1 (1573)

Name Changes:  Kitarō → Tatsuoki

Other Names:  Uhyōe Taifu, Jibu-no-Taifu, Isshiki 義糺, Isshiki 義輔, Isshiki 義棟, Isshiki 義紀, Isshiki Shikibu-no-Taifu

Rank:  sengoku daimyō

Clan:  Saitō, Isshiki

Bakufu:  Muromachi

Lord:  Ashikaga Yoshiteru → Ashikaga Yoshihide → Asakura Yoshikage

Father:  Saitō Yoshitatsu

Mother: Ōmi-no-kata (Ōmi-no-tsubone)

Wife:  Daughter of Azai Hisamasa (?)

Saitō Tatsuoki served as a sengoku daimyō during the Sengoku period.  Tatsuoki was the third head of Saitō Dōsan’s branch of the Saitō family in Mino Province (the second head of the Mino-Isshiki family).  His childhood name was Kitarō.

Family relationships

In 1548, Tatsuoki is said to have been born as the illegitimate son of Saitō Yoshitatsu, but if Ōmi-no-kata was his mother, he would be the son of Yoshitatsu’s formal wife, making him the eldest son and natural heir.  There is a theory that Ōmi-no-kata was the daughter of Azai Hisamasa  but there was only a one-year difference in age between Yoshitatsu and Hisamasa, so Ōmi-no-kata would not have been Hisamasa’s natural child but rather an adopted child.  Therefore, the prevailing view is that Ōmi-no-kata was the daughter of Azai Sukemasa, the father of Hisamasa.  If Dōsan was the father of Yoshitatsu, then Tatsuoki would have been his grandson.

Succession and loss of retainers

After the death of Yoshitatsu on 5/11 of Eiroku 4 (1561), Tatsuoki, became the head of the family at the age of fourteen.  Tatsuoki’s youth and inexperience shook the band of retainers so that, at once, the Saitō struggled to defend against invasions of Mino by Oda Nobunaga of neighboring Owari Province.  In the era of Yoshitatsu, attacks by the Oda focused on the western portion of the province.  Aware of the vulnerabilities of the Saitō clan under Tatsuoki, Nobunaga shifted his focus to the central portion of Mino, launching a conflict known as the Invasion of Chūnō.

Tatsuoki failed to earn the trust of his band of retainers.  In addition to his immaturity, Tatsuoki indulged in a decadent lifestyle and did not pay attention to affairs of governance.  Furthermore, he took care of only some of his close retainers such as Saitō Hida-no-kami (an unpopular figure) while alienating key retainers, including Takenaka Shigeharu and the Western Mino Group of Three (Andō Morinari, Inaba Yoshimichi, and Ujiie Naomoto) from governance of the clan.  Veterans serving the Saitō from the era of Tatsuoki’s grandfather (Dōsan) departed from the clan, including Mori Yoshinari, Sakai Masahisa, Hori Hideshige, Saitō Toshiharu, and Akechi Mitsuhide.

In 1561, at the Battle of Moribe, he prevailed in the clash, but lost senior retainers including Hibino Kiyozane and Nagai 衛安 who were counted among the Six Veterans of the Saitō.  In 1562, Endō Morikazu, the lord of Gujō-Hachiman Castle and a powerful retainer, died of illness.

Invasions by the Oda

In an effort to resist the invasion of Mino by Oda Nobunaga, Tatsuoki attempted to enter into an alliance with Azai Nagamasa of northern Ōmi Province.  In the past, Nagamasa had incurred invasions by Tatsuoki’s father, Yoshitatsu.  Tatsuoki, however, was forestalled by Nobunaga who had earlier allied with Nagamasa.  Instead of joining forces with Tatsuoki, Nagamasa invaded Mino, threatening Tatsuoki.  At this time, Rokkaku Yoshikata, the sengoku daimyō of southern Ōmi who was an ally with the Saitō from the era of Yoshitatsu, invaded the territory of the Azai in northern Ōmi.  As a result, Nagamasa halted his invasion of Mino and withdrew.

In 1563, after another invasion by the Oda, Tatsuoki fought against Nobunaga at Shinkanō.  Owing to the contributions of his retainers including Takenaka Shigeharu, the Saitō defeated the Oda at the Battle of Shinkanō.

Seizure of Inabayama Castle

At midday on 2/6 of Eiroku 7 (1564), Shigeharu joined his father-in-law, Morinari, to attack Tatsuoki at Inabayama Castle (later known as Gifu Castle), killing six people including Saitō Hida-no-kami (with whom Shigeharu had personal enmity), causing Tatsuoki to flee, first to Ukaizan Castle, and then Ikoyama Castle.

Taking advantage of the seizure of Inabayama Castle, Endō Tanetoshi (the lord of Gujō-Kigo Castle) attacked Hachiman Castle while Endō Yoshitaka fled to Kariyasu Castle.  The occupation of Inabayama Castle continued until around 7/29, and, in the eighth month, Tatsuoki appeared to have taken back the castle by force.  Although Tatsuoki resumed his position at the lord of Mino, this incident led to the breakdown of the Saitō family.  The construction of Komakiyama Castle by Nobunaga from 1562 increased the pressure on eastern Mino.  The Oda wielded influence in this area owing in part to their familial relationship with the Tōyama.  Powerful landowners including the Ichihashi, the Maruo, and the Takagi clans began to collude with the Oda.

In 1565, Satō Tadayoshi, the lord of Kajita Castle who betrayed the Saitō in favor of the Oda, killed Kishi Nobuchika, the lord of Dōhora Castle, who had remained committed to the Saitō to the end.  At this time, Nagai Michitoshi, Tatsuoki’s granduncle and lord of Seki Castle who had been a stalwart of the Saitō in Mino, was defeated by Saitō Toshiharu (serving as a retainer of the Oda).  Consequently, the central portion of Mino fell under the control of the Oda.  This occurred in the course of the Invasion of Chūnō.

In a letter of 11/13 of Eiroku 8 (1565) addressed to Isshiki Fujinaga, a bushi and member of the retinue known as the otomoshū serving the Ashikaga shōgun, he offered gifts of a long sword and horse.

In 1567, the Western Mino Group of Three (Andō Morinari, Inaba Yoshimichi, and Ujiie Naomoto) colluded with Nobunaga so Inabayama Castle was finally toppled by Nobunaga in the Siege of Inabayama Castle.  On 8/15, he went by boat down the Kiso River that flowed in the area below the castle, fleeing to Nagashima in Ise Province.  As a result, the Oda forces pursuing Tatsuoki attacked Nagashima.  At the time, he was twenty years old.  Thereafter, he did not return again as a daimyō in Mino Province.

Resistance to the Oda

After going into exile in Nagashima, Tatsuoki joined Nagai Michitoshi in the Nagashima Ikkō-ikki that began in 1570 to continue resistance to Nobunaga.  Thereafter, he moved from Ise to the Kinai, and, in the first month of 1569, conspired with the Miyoshi Group of Three in a plot to attack and kill Ashikaga Yoshiaki, the fifteenth shōgun of the Muromachi bakufu backed by Nobunaga, but were defeated in the Battle of Honkoku Temple.  In the eighth month of 1570, Tatsuoki joined Miyoshi Yasunaga, Atagi Nobuyasu, and Sogō Masayasu, along with Kennyo, the eleventh high priest of the Hongan Temple, to support a defense by the Miyoshi Group of Three at the Battle of Noda and Fukushima Castles.  The forces held-out until the Oda withdrew owing to the threat of attack from behind by Asakura Yoshikage and Azai Nagamasa.


Thereafter, Tatsuoki relied upon his family relationship with the Asakura to flee for protection  under Asakura Yoshikage of Echizen Province where he was treated as a guest commander.

In the eighth month of 1571, Kennyo sent a letter to Isshiki Shikibu no Tayū (Tatsuoki) offering wishes that Tatsuoki achieve his goals and presenting him with gold pieces and a long sword.  A letter from the eighth month of 1572 from Jōryō of the Annyō Temple in the Gujō District of Mino and Senshō from the Saishō Temple in the Ōno District of Echizen to Shimotsuma Raitan, a head monk at the Hongan Temple, describes the status of plans for Lord Isshiki to enter the province for which the Hongan Temple ordered the cooperation of followers in the Gujō and Ōno districts.  A letter from the first month of the same year from Tatsuoki to Jōryō notes that Senshō persuaded the Endō clan and that he planned to send Hineno Hironari to Nagashima but the plans were delayed owing to the illness of Senshō.

These writings reveal a plan by which Tatsuoki (with the support of the Asakura clan and adherents from Echizen and Mino) would come from Echizen in the north while Hironari (with the support of adherents from Nagashima) would come from Ise in the south to launch a pincer attack against their opponents in Mino.  A letter from Kennyo in the winter of the same year suggests that such a plan was in fact executed.  However, owing to snowfall, the Asakura army pulled back to Echizen so Tatsuoki was not able to reclaim Mino and restore his authority.  Meanwhile, it appears that he also pulled back to Echizen.

In the eighth month of 1573, when Asakura Yoshikage deployed to northern Ōmi in support of Azai Nagamasa for a showdown against Nobunaga, Tatsuoki joined the effort.  On 8/14, however, after the Asakura army was defeated by the Oda, Tatsuoki was killed at Tonezaka in the ensuing pursuit by Oda forces.  This event is known as the Battle of Tonezaka or the Siege of Ichijōdani Castle that resulted in the annihilation of the Asakura clan.

According to one theory, he was cut-down by Ujiie Naomasa, the eldest son of Ujiie Naomoto, a former senior retainer.  Tatsuoki was twenty-six years old.

Alternative theories regarding demise

There are several theories proposing that Tatsuoki combined with the Hongan Temple forces and lived beyond the Battle of Tonezaka.

According to one theory, Tatsuoki was not killed in action, and, instead, carrying his family genealogy, in the third month of 1569, went to the village of Nunoichi in the Niikawa District of Etchū and hid at the Kōkoku Temple.  Acknowledging that under the circumstances he would not be able to revive the Saitō family in Mino, he changed his name to Kyūeimon and cultivated the nearby fields.  Residing in this area, he said that cultivation was the strength of Buddha and also became the strength of his believers, providing encouragement to family members.

After the end of the Ishiyama War between Nobunaga and the Hongan Temple in 1580, he named this area the village of Kyōriki.  In 1611, Tatsuoki transferred headship of the clan to his son, donated crops, and entered the priesthood at the Kōkoku Temple in Nunoichi, and became its abbot.  At the Kōkoku Temple are an armored saddle and wooden statue of Buddha (Amitābha) that are said to have been brought by Tatsuoki.

He died as a high-ranking priest on 6/19 of Kanei 9 (1632) and his grave is in front of the Honsei Temple in Kyōriki in Tōyama.  He was eighty-seven years old.

In the eleventh month of Bunsei 3 (1820), his descendants moved to the village of Ōizumi in the Niikawa District of Etchū Province, and, in the eleventh month of Taishō 2 (1913), to Koizumi in the village of Horikawa in the Niikawa District.

There is a story that Tatsuoki fled the Battle of Tonezaka and converged with members of the Hongan Temple.  He proceeded to the Ishiyama-Hongan Temple and joined with forces from the temple in a bid for a revival, but then died of illness at a temple in the present-day town of Ajika in the city of Hashima in Gifu.  At the Gankyō Temple, there is a grave for Tatsuoki and his father, Yoshitatsu, along with a mortuary tablet for Tatsuoki’s son, Kohei-Yoshihito.

Religious affiliations

While residing in the Kinai, Tatsuoki aimed to become a Christian.  Luís Fróis, a Jesuit missionary from Portugal who resided in Japan during this period, taught Tatsuoki the beliefs of the Christian religion including creationism, for which Tatsuoki took copious notes.  While attending a church service, Tatsuoki was able to fluently recite without error what he learned, surprising the worshipers in attendance.  In regard to Tatsuoki, Fróis noted in his diaries that Tatsuoki was a highly capable and thoughtful individual.

To Gaspar Vilela, the first Jesuit missionary to arrive in Japan and who initiated evangelical activities in Kyōto, Tatsuoki raised these questions: The priests say that mankind is blessed by Deus (meaning God in Latin) and assured of being at the apex of all beings.  If that is the case, then in the world of man, why are is there so much misfortune and never-ending war?  If mankind was created to be at the apex of all beings, why doesn’t the world easily abide by man’s will?  And, in this tumultuous world, for those individuals who endeavor to lead good lives, why can’t they receive any rewards in this world?  In response to these questions, it is noted that Vilela provided convincing explanations.


It is noted that when Yoshitatsu (Tatsuoki’s father), rebelled against Dōsan (Tatsuoki’s grandfather), Yoshitatsu adopted the surname of his mother (Isshiki) and Tatsuoki adopted the surname as well.  However, it is further noted that the Isshiki name does not appear in many of the historical materials relating to Tatsuoki.  Meanwhile, in the era when Tatsuoki served as head of the Mino-Saitō family, he received one of the characters from the name of the Ashikaga shōgun family and adopted the first name of Yoshimune.  After the end of the Saitō clan, the band of retainers changed their surnames to those of the Isshiki family.  For example, Hineno Hironari adopted the surname of the Nobunaga clan who served as the deputy military governors under the Isshiki family.

In connection with the theory that Tatsuoki was a native of Etchū, there is a story that a crane led him to the location of a mineral bath in Tōyama called the Kyōriki Bath which operated for many years and was also the site where Christians (who worshiped in secret owing to the prohibition against Christianity by the Edo bakufu) were taken after being apprehended during the late Edo period.  The Kyōriki Bath ceased operations in 1917 and a wooden statue of a Buddha known as Bhaiṣajyaguru worshiped there was moved to the Honsei Temple.  A painting of a winter scene of the Kyōriki Bath previously owned by Maeda Toshitsuyo, the ninth head of the Tōyama domain, was given to the city of Kanazawa in Ishikawa Prefecture.