Yagi-jo Castle (Tanba Province) (八木城 (丹波国))

Yagi-jo Castle was a castle which existed in the vicinity of Yagi, Yagi-cho, Nantan City, Kyoto Prefecture and Kozaki, Miyazaki-cho, Kameoka City. It was famous as the castle associated with Joan NAITO. It was one of the three major castles of Tanba Province; Kuroi-jo Castle, Yakami-jo Castle, Yagi-jo Castle.


It was a multiple teikaku-shiki (the central compound is placed adjacent to the castle walls, and additional compounds are placed surrounding the honmaru) mountain castle which stood at an altitude of 344 m to the southwest of JR West Yagi Station. The castle was vast, with the central compound built on the top of the mountain and various defenses such as additional compounds built on branching ridges. Even today, remnants of the central compound, tenshudai (independent raised foundation upon which the castle keep was constructed) and stone walls can be seen on the surface of the ground. However, there are many unknown factors regarding the history of the castle. There are many historical sources that describe Yagi-jo Castle including "Taikoki" (Chronicle of Hideyoshi TOYOTOMI), "Akechi Gunki" (Biography of Mitsuhide AKECHI), "Tanba Fudoki" (Tanba Province Gazetteer), "Tanba Kohaiki" (The Rise and Fall of Tanba), "Momi-ke Nikki" (Diary of the Momi Family), "Naito Seisuiki" (The Rise and Fall of the Naito Clan), and "Yagi-cho Shi" (Yagi Town Journal"). "Nihon Jokaku Taikei" (Compendium of Japanese Castles) postulates that many mistakes have arisen due to the citation of these historical sources without sufficient examination of the original documents, and further secondary citations. Aside from the fact that it was the residence of the Naito clan (Tanba branch), there are many points which are unclear regarding the lifetime and genealogy of the castle. Yagi-jo Castle is a well-known mountain castle but there are many unclear points.


It is said that the history of Yagi-jo Castle began when Akikatsu NAITO (also called Sadafusa) entered Yagi having been granted the Funai district in 1335 because of his military exploits when his army fought alongside Takauji ASHIKAGA in Shinomura Tanba Hachiman-gu Shrine in 1333.
In the July 24, 1431 entry of "Mansai Jugo Nikki" it is stated that `Under the order of Shogun Yoshinori, Mochiyuki replaced Kazai with Naito Bizen Nyudo as Shugodai (deputy of Shugo (provincial constable)).'
It is assumed that the fact that Naito Bizen Nyudo, also known as Nobusuke NAITO, who had been the hikan (low-level bureaucrat) of the Hosokawa clan became the Shugodai of Tanba Province facilitated the full-scale expansion of Yagi-jo Castle for the reason that Yagi-jo Castle displayed the power of the Naito clan which served as Shugodai. It appears as though Nobusuke had died or been replaced in 1442 or 1443, and Koresada NAITO was assigned as the subsequent Shugodai (deputy of Shugo, provincial constable) of Tanba Province in June 1443. It seems that he was replaced by Motosada NAITO between 1449 and 1452. It seems that Motohide UEHARA subsequently became the Shugodai of Tanba Province in January 1483. However, it appears that he died in December 1493, after becoming wounded in a dispute with Yaroku NAGASHIO in November in the same year.

In the August 24, 1495 entry of "Daijoin jisha zojiki" (Miscellaneous Records of the Daijo Temple and Shrine), it is stated that Hosokawa entered Tanba Province, and newly appointed Naito as Shugodai. The text states that Motosada NAITO reassumed the position of Shugodai after the downfall of Motohide UEHARA's son, Kataie UEHARA. It is regarded that Sadamasa NAITO subsequently became Shugodai until between 1505 and 1521, when he was succeeded by Kunisada NAITO. However, Yagi-jo Castle came to serve as a battlefield several times, after Kunisada NAITO allied with Ujitsuna HOSOKAWA and Nagayoshi MIYOSHI. According to sources including "Hosokawa Ryoke Ki " (Record of the two houses of Hosokawa), when Yagi-jo Castle fell in October, 1553, Kunisada NAITO also died in the battle. After that, Hisahide MATSUNAGA's younger brother, Nagayori MATSUNAGA regained Yagi-jo Castle. Nagayori MATSUNAGA, along with Kazumasa SOGO, achieved success in war earlier than other members of the Miyoshi clan force. He is believed to have been someone who was deeply trusted by Nagayoshi MIYOSHI.
"Sengoku Miyoshi ichizoku" states that 'It was mainly due to his (Nagayori MATSUNAGA) tactical skill that Tanba Province remained the territory of the Miyoshi clan for 13 years.'
According to "Tamonin Nikki," it appears that this tactical genius was killed in an attack by Naomasa AKAI in September 1565.

The period of Joan NAITO

As the residence of Joan NAITO, Yagi-jo Castle was under the Kinkyo-rei (Edicts banning Christianity). To avoid future trouble, it appears that many historical materials were intentionally rewritten and records were destroyed, making it extremely difficult to ascertain the truth. This is why Yagi-jo Castle is called 'Maboroshi no Yagi-jo' (lit. The Phantom Castle of Yagi-jo), and research into Yagi-jo Castle continues even now.

The mother of Joan NAITO was a daughter of Sadafusa NAITO (according to an article by Motoo YAGI entitled "Tanba Yagi-jo Castle and Joan NAITO," Sadafusa may be an error for what should be Kunisada). She married into the Azai clan in Omi Province, and had a child but returned to Yagi-jo Castle with her child after her husband died. The name of her child was Genba YAGI, and served as a karo (chief retainer) after becoming the brother-in-law of Joan NAITO. The mother of Joan NAITO subsequently remarried into the Hosokawa clan, but she once again returned to Yagi-jo Castle after her husband died. It was under these circumstances that the mother of Joan NAITO remarried for the third time to Nagayori MATSUNAGA, with whom she had two children. They were Joan NAITO, who later became Goromaru, and his sister Julia NAITO. On the other hand, "Sengoku Miyoshi Ichizoku" states that 'Joan NAITO is assumed to be the birth child or the adopted child of Nagayori MATSUNAGA,' indicating the possibility that he may have been adopted.

The power of Motokiyo HATANO, lord of Yagi-jo Castle had been expanding since circa 1553, and began to threaten Tanba Province. The lord of Yagi-jo Castle at that time, Kunisada NAITO, was killed in the battle of Honbaigo, and Sadafusa NAITO who entrenched himself in Yagi-jo Castle was also killed, thus, the castle fell to the army of Motokiyo HATANO. The birth child of Kunisada NAITO, Senkatsumaru, was saved and kept at Sonobe-jo Castle by Munesada YUASA. Nagayori MATSUNAGA was enraged by the falling of Yagi-jo Castle, and left another battle, successfully retaking Yagi-jo Castle after a fierce fight.

"Ashikaga Kiseiki" (a military epic of Ashikaga) states that 'Matsunaga is a son-in-law of Naito - a provincial governor of Bizen, and he is a dependable man in the castle particularly; the losers attempted to take over the castle, but he threw them over and took all the credit of war' regarding the fierce fight at that time. The Shogun granted him the family name "Naito" was a reward for his achievement, and it seems that he changed his name to Munekatsu NAITO.

Meanwhile, Joan NAITO associated with a woman who had fled to Yagi-jo Castle from the direction of Yamaguchi Prefecture due to a family feud. Her name was Katarina, and only her Christian name was known according to "Kyodoshi Yagi" (Local History of Yagi). In "Naito Joan no Shogai" (The Life of Joan Naito), the 'family feud' in Yamaguchi Prefecture was assumed to be the Rebellion of Sue Takafusa (Taineiji no hen, the revolt of Taineiji). Katarina brought up Goromaru and his younger sister, Julia as if they were her own children. Goromaru and Julia entered the Christian faith under the influence of Katarina. It is thought that in June 1565, they were christened by Luis Frois at Nanban-dera Temple in Kyoto and his Christian name, Joan was given to him at that time.

Meanwhile, the lord of Kuroi-jo Castle, Naomasa AKAI who was dreaded as the 'Red Ogre of Tanba' and the lord of Yagami-jo Castle started a revolt to conquer Tanba Province from Hideharu HATANO, and in September 1565, Nagayori MATSUNAGA led an expedition with more than 700 soldiers. As they reached Hikami District, it began to rain heavily at dusk and they set up camp at a nearby temple. However, a monk of the temple betrayed them to Naomasa AKAI, and they were suddenly attacked during the night. Nagayori MATSUNAGA led 700 soldiers and fought hard, but it appears that almost all of the soldiers died with honor. Thus, Joan NAITO lost his father three months after he was christened.

After losing his father, it seems that Joan NAITO became lord of Yagi-jo Castle, and actively conducted missionary work centered around Yagi-jo Castle. As far as it is evident from current records, it seems that he invited the Japanese missionary, Lorenzo RYOSAI, on three occasions. Lorenzo RYOSAI was a disciple of Luis Frois, and he was said to have converted as many as 6,000 people to Christianity from Kyushu to Kyoto. Lorenzo RYOSAI visited Yagi-jo Castle twice between 1572 and 1573. In a letter from Gaspar VILELA, Lorenzo's second visit in the early part of 1573 is described as follows: Padre Organtino and Lorenzo arrived there from Sanga eight days ago, and because Naito and his subordinates visited Tanba Province to listen to his preaching, Lorenzo left there with the emissary the day before yesterday. An account of the third visit in 1574 in an unpublished correspondence by Luis Frois states that Frois and Lorenzo followed the mountain path from the capital to Tanba. After walking about five miles, Joan NAITO welcomed them with his retainer. A gorgeous altar was installed in his castle. Over eight days, 70 soldiers were baptized, followed by 14 more. Yagi-jo Castle was becoming the base of missionary work by the Society of Jesus in Tanba Province.

Around this time, infighting began between the group aiming to install Joan NAITO as a lord of the castle and the group backing the birth child of Kunisada NAITO, Senshomaru (later known as Sadakatsu NAITO). The brothers of Sadafusa NAITO were Buddhist monks, and rebelled at every opportunity against Nagayori MATSUNAGA who did not have a blood relationship with the Naito clan. It appears that Joan NAITO's uncles forced his mother to abandon plans to install Joan as the lord and to convert to Christianity. However, it seems that Joan's mother was strong willed, and she was killed by the monks because of her resolute refusal to comply. Therefore Joan NAITO lost his mother after previously losing his father. "Naito Joan no Shogai" (The Life of Joan Naito) surmises that his mother was killed between autumn and the end of 1573. "Frois's History of Japan" states that after his mother's death, Joan NAITO did not care at all about his position as the lord of the castle, and drifted throughout the country, becoming increasingly involved in his faith.

Thereafter, Joan NAITO became a guest commander of Yukinaga KONISHI, and went to fight in the Bunroku-Keicho War in which he played an active role. He fled to Manila with Ukon TAKAYAMA after the Tokugawa shogunate enacted the Kirishitan Kinkyo-rei (Edicts banning Christianity). In Manila, he was welcomed and treated as if he were a living god, and seems to have been loved by the local people. It is said that he was surrounded by his wife Maria, younger sister Julia, his children, and the local missionaries and monks when he passed away. He was aged 73.

The Battle of Yagi-jo Castle

In 1579, Nobunaga Oda's army with Mitsuhide AKECHI as supreme commander launched the second campaign for the conquest of Tanba Province which focused on Yagami-jo Castle and Kuroi-jo Castle. With the fall of Ayabe-jo Castle and Tamaki-jo Castle in June 1579, Nagahide NIWA and Hidenaga HASHIBA were commanded by Hideyoshi HASHIBA provide reinforcements for the Battle of the Miki-jo Castle, and fought in numerous battles. In July of the same year, they launched a battle against the lord of Yagi-jo Castle, Arikatsu NAITO who had a certain degree of power in the area at the time, and attacked Yagi-jo Castle.

Yagi-jo Castle, being a robust castle utilizing its rough landscape, could not be taken easily, and Mitsuhide AKECHI offered peace negotiations to Arikatsu NAITO. However, Arikatsu NAITO refused his offer and continued to defend.

Mitsuhide AKECHI attempted to solicit someone as a betrayer within Yagi-jo Castle, and the person who accepted his offer set a fire in the honmaru (main compound) and the ninomaru (secondary compound) of Yagi-jo Castle. With the fire serving as a signal, Mitsuhide AKECHI's army attacked in full force, and Yagi-jo Castle finally fell. This was on July 30 in the same year. It is thought that the lord of Yagi-jo Castle, Arikatsu NAITO died in battle at this time.

A member of the Naito clan, Masakatsu NAITO, attempted to break through Mitsuhide AKECHI's forces and head for Hatta-jo Castle. While fleeing to Hatta-jo Castle, some soldiers were separated from his army and killed themselves, and Masakatsu NAITO entered Kogadake-jo Castle, where he is thought to have died. Thus, the Naito clan which had been existed since the Muromachi period died out.

This battle was mainly described in "Naito Seisuiki" (The Rise and Fall of the Naito Clan), but it is not well understood what type of people Arikatsu NAITO and Masakatsu NAITO were.
According to Motoo YAGI's research, 'Arikatsu as described in "Naito Seisuiki" was fictional and achievements of Joan were conferred upon Arikatsu, and the name of Joan extinguished.'
In the part when Yagi-jo Castle was fallen, Motoo YAGI expressed his view that it was not fictional. In Kiichi MATSUDA's article, "Tanba Yagi-jo Castle and Joan NAITO," he indicated that Joan NAITO was not present at the battle of Yagi-jo Castle because 'Joan moved to Izumi Sakai and then went to the place of Yoshiaki ASHIKAGA after the autumn of 1574' subsequent to the conflict between the allies Nobunaga ODA and Yoshiaki ASHIKAGA. In any case, any materials disclosing the whereabouts if Joan during this time were altered, and there are no definitive surviving sources.

Abandonment of Yagi-jo Castle

It is not clear exactly when Yagi-jo Castle was abandoned. Katsuhiko FUKUSHIMA pointed out that Yagi-jo Castle was renovated by Mitsuhide AKECHI. Excavations were conducted in conjunction with the construction of the National Route 478 bypass. According to "Kyoto Prefecture Ruins Investigation Summary," it is highly likely that the excavation site was heavily influenced by Mitsuhide AKECHI, and the artifacts that were found in the site, also indicate aspects strongly characteristic of the period of Mitsuhide AKECHI. After the demise of the Naito clan, Mitsuhide AKECHI who conquered Tanba Province constructed Kameyama-jo Castle (Tanba Province), and the center of Tanba Province shifted to Kameyama-jo Castle. It appears that Yagi-jo Castle was not deserted, and continued to function as a subsidiary castle of Kameyama-jo Castle.

Honmaru (Main Compound)

The honmaru was situated on a plateau raised above and left side of the stable walls. It measured 10 m from north to south, and was 13 m from east to west. There is a surviving "Yagi-jo Koezu" (an old sketch map of Yagi-jo Castle) which was measured and created by Sazaemon KIDOKORO and Toemon AKAI. This depicts gobozumi (stone walls comprised of roughly cut or naturally formed rocks that are shaped like a burdock) stone walls on four sides. Today, the stone walls are covered with about 60 cm of mud, and cannot be seen. Even though Yagi-jo Castle fell into the hands of the enemy during the battle, it seems that they didn't burn it down given that no traces of embers have been found there.

Kin-no-Ma Compound

The Kin-no-Ma compound projects from the west side of the honmaru. Judging by its name, the Kin-no-Ma (lit. Gold Room), compound is assumed to have been a treasure store. According to "Yagi-jo Koezu," there was one compound for which the stone walls were built using a special arrangement of stones. This has been associated with the treasure store. However, the shape of the tenshudai (raised foundation upon which the principal tower was constructed), which was an important part of a castle, has been remarked upon as being more significant than the compound's name. Another similar tenshudai (raised foundation upon which the principal tower was constructed) has been unearthed in the excavation of Nagayori MATSUNAGA's Waroji-jo Castle. It is also included in "Yagi-jo Koezu" as a transition toward early modern tenshudai.

Okugata Yashiki Compound

A stepped compound was located on the northeast side of the honmaru. The largest area of this was believed to be the okugata yashiki (lit. wives' residence) compound described in "Yagi-jo Koezu." It is assumed from its name that it was the place where the family members or retainers of feudal lords spent their time on the mountain.

Ninomaru (Secondary Compound)

The stable compound was located to the southwest of the honmaru on flat land one level below the honmaru. Further left is a 3 m high cliff. Upon ascending this cliff, one will reach a flat area on which the ninomaru was located. The ninomaru is quite large, and both sides are sheer. It is thought that the residence of Goro NAITO may have been located here.

Other Compounds

There are other compounds in addition to those described above.

八木玄蓄 Residence Compound
Upon exiting the ninomaru and descending the slope, one will encounter a small hill. It is said that this is the site on which the residence of chief retainer 八木玄蓄 once stood. 八木玄蓄 was Joan's elder brother-in-law. This compound was thickly wooded and difficult to see, and the platform projected out to the left while below was a deep valley known as 玄蓄谷.

Sannomaru (Tertiary Compound)
Proceeding further along the ridge from 八木玄蓄's residence compound leads to a higher peak called the Eboshi-dake Mountain. This was the sannomaru where the chief retainer of the former castle lord resided. There are two large caves in which manganese ore was mined during the Taisho period.

Eastern Demaru (Opposing Compound)
Because the road that passed by this eastern demaru (small castle or tower built onto and projecting from a larger castle) was the main road, it is though that an otemon (main gate) once stood in the vicinity of this compound. It is said that a tsumesyo (station) for a sosha (an official in charge of informing a shogun or daimyo of the name of visitors to the residence before a meeting) was located in the eastern demaru. It is presumed that emissaries or guests would first wait in the tsumesyo while the sosha went to the opposing compound to report to and obtain instructions from castle officials. The road is called 'Sosha Pass' even today.

There were also other compounds such as the northern demaru, the northern maguchi (exit) and the residential compound, as well as entrances including Iwaya-guchi (lit. Cave Gate), Tatsu-no-guchi (lit. Dragon Gate), Toramatsu-guchi (lit. Tiger and Pine Gate) and Sugitani-guchi (lit. Cedar Valley Gate).


Numerous excavations focusing on the residential compound at the base of the mountain have been conducted including the investigation accompanying the construction the National Route 478 bypass.

These have unearthed structural remains of a residence protected by a stone wall, small caves with rock arrangements, stone wells, terraces created by digging into the valley walls, and some foundation stones. Artifacts unearthed include Haji plates and Chinese porcelain. These excavations also discovered a kiln dating from the latter part of the Kofun period (tumulus period) that was used to fire sueki (unglazed ceramics).

Access to the castle site

By train
Alight at Yagi Station on the JR West Sagano Line and walk for approximately 15 minutes from Kasuga-jinja Shrine.
By car
Take National Route 9 to Kasuga-jinja Shrine from the Yagi Higashi Interchange of the Kyoto Jukan Expressway. No parking facilities available in the vicinity.
On foot
Approximately 35 minutes' walk from Kasuga-jinja Shrine to the honmaru at the peak.

[Original Japanese]