Siege of Arioka Castle


Oda Clan

Settsu Province

Araki Clan

Dates:  Seventh month of Tenshō 6 (1578) to 10/19 of Tenshō 7 (1579)

Location:  Arioka Castle and its environs in the Kawabe District of Settsu Province

Outcome:  An unexpected rebellion by Araki Murashige led to a long siege by the Oda forces of Arioka Castle.  In the end, he slipped away at night to Amagasaki Castle, and after broken promises by Araki Kyūzaemon, the Oda exacted revenge by killing a large number of Araki family members and retainers.

Commanders:  Oda Nobunaga, Oda Nobutada, Takigawa Kazumasu, Tsuda Nobuzumi, Saitō Toshiharu, Akechi Mitsuhide, Hachiya Yoritaka, Ujiie Naomasa, Andō Morinari, Inaba Yoshimichi, Hashiba Hideyoshi, Hosokawa Fujitaka, Ikeda Tsuneoki, Niwa Nagahide

Forces:  50,000

Casualties:  2,000 soldiers on a single day; other numbers unknown

Commanders:  Araki Murashige, Araki Muratsugu, Araki Shigekata, Takayama Ukon, Nakagawa Kiyohide

Forces:  10,000 to 15,000 → 5,000 (after majority fled)

Casualties:  Unknown, but 670 members of the Araki family and their retainers were slaughtered by the Oda after the castle was vacated

The Siege of Arioka Castle occurred from the seventh month of Tenshō 6 (1578) to 10/19 of Tenshō 7 (1579).  This was a castle siege that was triggered when Araki Murashige (a senior retainer of Oda Nobunaga) suddenly launched a rebellion.  This conflict is also known as the Siege of Itami Castle.

Details of the hostilities

In the seventh month of 1578, Murashige participated in the Battle of Miki and affiliated with the army of Hashiba Hideyoshi, then he suddenly left the battle front and returned to his home base at Arioka Castle (also known as Itami Castle).  This was a rebellion against Oda Nobunaga.

The reason for his rebellion may have owed to Nobunaga’s severe attitude toward his subordinates.  Murashige was said to be from the Hatano clan and received an official appointment from Nobunaga as the military governor of Settsu with a fief of 370,000 koku.  According to one account, a rumor circulated that Murashige colluded with the Mōri forces to secretly bring in military provisions to the Ishiyama-Hongan Temple while Nobunaga clashed with them at the Battle of Ishiyama.  When, upon orders from Nobunaga, he departed to negotiate a settlement with the opponents, he noticed the impoverished conditions in the castle, and, to make the negotiations proceed well, contributed 100 koku of rice himself. 

In another account, during a siege of Kanki Castle in the Innami District of Harima, a betrayer within the castle named Kanki Sadamitsu was an old acquaintance of Murashige so, after the fall of the castle, Hashiba Hideyoshi spared his life.  Immediately thereafter, however, Sadamitsu fled for the protection of Bessho Nagaharu, and because Sadamitsu was in contact with Murashige, Murashige also became the subject of suspicion.  Another view focuses on the situation in Settsu, whereby kokujin, or provincial landowners, and peasants in the province opposed the strengthening of governance by the Oda administration, causing a sudden increase in the level of resistance.  Being provoked from this grassroots movement, Murashige opted to part ways with Nobunaga and act in concert with the locals before being expelled by them.  Consequently, there are numerous theories in regard to the reasons for his rebellion but the details remain uncertain.

Surprised at the rebellion by Murashige, Nobunaga dispatched Akechi Mitsuhide, Matsui Yūkan, and Mami Shigemoto as messengers to establish the facts through thorough examination​.  Mitsuhide’s daughter was married to Murashige’s eldest son, Araki Muratsugu, so he may have been chosen owing to this relationship.  Meanwhile, Takayama Ukon of Takase Castle also headed to Arioka Castle in an effort to persuade Murashige against rebelling.  He reminded Murashige of the rewards received from Nobunaga, that it would be impossible to defeat Nobunaga, and that he would be subject to severe punishment when he lost.  To dispel their suspicions, and despite having already tendered two hostages, Ukon also gave his eldest son as another hostage.

Murashige initially listened to these arguments, endeavored to vindicate himself by offering his mother as a hostage, and headed with his son toward Azuchi Castle.  However, after stopping at Ibaraki Castle along the route, his retainers received a notice stating that if he goes to Azuchi Castle, he will be made to commit seppuku and war will spread across Settsu, whereupon he was restrained by Nakagawa Kiyohide.  According to another account, Murashige’s retainers came and said they had no intention of following Nobunaga and that if Murashige does not promptly return to Settsu, they would make someone else lord of the territory.  Murashige then reluctantly returned to Arioka Castle and made clear his rebellion.

There were some in the Oda army who did not take well to Murashige’s rise.  Hosokawa Fujitaka gave Nobunaga a statement of principles for rebellion and told Nobunaga that Murashige intended to rebel.  With respect to a confrontation with Nobunaga, Murashige tendered hostages and, via Ashikaga Yoshiaki, Mōri Terumoto, and Kennyo (the abbot of the Ishiyama-Hongan Temple of the Jōdō sect), a written pledge to ally with Nobunaga.  The pledge stated:

  • Regarding my association with the Hongan Temple, I will consult in regard to good and evil and put my heart and soul into it.  I will accept the demands of the Hongan Temple.  Without regard to the future state of affairs after the overthrow of Nobunaga, the Hongan Temple will not abandon the Araki clan.
  • The Hongan Temple will not interfere in my fief and I have no objection to the holdings of the Hongan Temple.  The Araki will govern peasant followers and the Hongan Temple will not interfere.
  • The Hongan Temple will not discuss the affairs of Settsu Province and will not interfere in matters involving the desired fiefs in other provinces.   I will act loyally toward the bakufu authority and the Mōri so the Hongan Temple will make its best effort to respect those desires.  Moreover, the Hongan Temple will expel masterless bushi who fight against the Araki.

Further, Mitsuhide’s daughter who was married to Muratsugu was separated and returned to Mitsuhide.  After receiving this news, Nobunaga sent Fukutomi Naokatsu and Sakuma Nobumori and, on 11/3 of the same year, moved to Nijō Castle.  He then had Mitsuhide, Matsui Yūkan, and Hashiba Hideyoshi head to Arioka Castle.  Murashige responded by saying that he had no ambition but refused Nobunaga’s demand to tender his mother as a hostage and negotiations broke down.  Thereafter, Kodera Yoshitaka (Kuroda Yoshitaka) came by himself to Arioka Castle but was then incarcerated by Murashige.  It is surmised that he was taken and put in the gaol just before Kodera Masatomo, an ally of Yoshitaka, arrived.

Battle situation

The dispute between the two sides became definitive so, to prepare for the Oda army, Murashige positioned his commanders over a broad area, as noted in the description of the army.

Nobunaga earlier ordered Murashige to construct and renovate Arioka Castle to prepare for an encirclement in the Battle of Ishiyama.  Meanwhile, Nobunaga understood that it would not be a good idea to turn into enemies both the Ishiyama-Hongan Temple and Murashige, so he sent Murai Sadakatsu as a messenger to propose a settlement with the temple.  The temple required consent from the Mōri clan so did not immediately respond positively to the offer.
On 11/6, at the Second Battle of Kizugawa, the steel-plated warships of the Oda navy launched attacks and roundly defeated the Mōri navy.  After their supply lines were cut, the military power of the Ishiyama-Hongan Temple appeared to have somewhat diminished.  On 11/9, Nobunaga marched 50,000 soldiers to Yamazaki on the border of Yamashiro and Settsu provinces.  On the next day, Takigawa Kazumasu, Akechi Mitsuhide, Hachiya Yoritaka, Ujiie Naomasa, and Andō Morinari laid siege to Ibaraki Castle and cut-through the Araki army.
Service to the Takayama
Takayama Tomoteru and his son, Takayama Ukon, were ardent Christian daimyō based in Takase Castle in the Shimakami District of Settsu who sided with the Araki.  This shook the Christian missionaries in Kyōto because, in Japan, they had instructed their followers not in any way to betray their lords.  Numerous Christians located in the town of Takase also feared becoming victims of a war.
An Italian Catholic missionary named Organtino Gnecchi‐Soldo informed Ukon to carefully consider that no matter what happened he would not oppose Nobunaga.  Ukon noted that he did not know how the situation could be resolved if even hostages could not be returned between the sides.  Not only were their lives in danger, at the time, it was very dishonorable to allow hostages to be executed.  Organtino was then concerned that Nobunaga would harm Christians.

Nobunaga sent a messenger to Organtino, and that for Ukon to side with the Araki was not permitted under Christian teachings.  If Ukon did not side with the Araki, Nobunaga offered to grant him as much territory and funds as desired.  Organtino responded that, if Ukon feared execution of the hostages and had to decide next steps, based on his character, money and territory were not needed to persuade him and that he would make the effort to try and persuade him.  Nevertheless, the situation did not progress.

Nobunaga called upon Organtino to discuss a means for recovering the hostages.  Nobunaga proposed an exchange of the hostages tendered by Murashige with hostages from Ukon, and, at the same time, if the hostages from Ukon were executed, he would settle the matter by providing notice in Kyōto and Sakai that their execution was not a result of the betrayal or ambition of Ukon so Ukon would not lose his honor.  He further proposed that he would listen to the wishes of the missionaries and support their evangelical activities.

Tomoteru and Ukon responded that if the hostages are simply returned, they would side with Nobunaga so he should wait four or five days before attacking Settsu.  Based on the sequence of time, Nobunaga is believed to have then been at an encampment in Ama in Takase.  To speed-up the situation, Nobunaga determined it would be a good plan to apprehend missionaries and inform the Takayama, so he ordered João Francisco, Lorenzo Ryōsai, and two others to be taken to Ōmi.  Meanwhile, Organtino sent a letter of parting to Lorenzo saying that he was deeply saddened and full of pain believing that they could not meet again in this life.

Upon learning of these developments, the Araki and their retainers in Takase Castle were persuaded and finally reached consensus to submit to Nobunaga on the condition that they receive their original territory and nothing else.  Nobunaga, however, did not agree to the proposal.  Although he agreed to the request from Organtino not to burn down the lands in Takase until the hostage situation is resolved, on 11/9, Nobunaga finally deployed himself to Settsu.

On 11/10, Nobunaga summoned all religious believers (including Organtino) in Kyōto and ordered them to use all of their power to make Ukon surrender.  He said if they do so, then they can build churches wherever they desire and, if they do not do so, he would prohibit their activities.  Organtino once again sent a messenger to Takase Castle, but subordinates of the Araki were already in the area around the castle, while, owing to his own suspicions, Takayama Tomoteru refused to listen and ordered all of the messengers attempting to enter the castle to be killed.  Sakuma Nobumori promised a contingent award of 16,000 koku to a band of Christian bushi from Takase, but to no avail.  Organtino fell into the deepest sense of worry and despair.  He believed that if the Takayama persisted in this way, then Nobunaga would aim to eliminate the Christians through the five provinces in Kinai, and, in fact, the churches in Kyōto were under the supervision of retainers of Murai Sadakatsu, and upon a single order from Nobunaga, would be attacked.

Ultimately, Organtino decided to venture himself to Takase Castle in a bid to convince them to change course.  He believed that, even if he failed, he would have performed his duty to do the utmost to resolve the situation.  It was anticipated that the soldiers at Takase Castle would kill him, so Organtino and Lorenzo pretended that they had fled from under Nobunaga and succeeded in obtaining protection at Takase.  Soon after entering the castle, they met with Tomoteru so, while Organtino maintained the pretense for coming, he explored Tomoteru’s intentions regarding surrender.  However, they could not obtain any information nor even meet Ukon.  When he attempted to report the situation to Nobunaga, four monitors were assigned so there were no options remaining.

Just when it appeared that nothing more could be done, an update came that Ukon had been persuaded by his retainers.  The solution identified by Ukon to save both the hostages and the Christians was for him to take the rites of tonsure and to relinquish all of his territory, his stipend, and his retainers.  He would not be backing Nobunaga by means of the soldiers and castle so the hostages would not likely be executed.

Around 10:00 PM, after Ukon left a letter for his father, he kept the plan secret and departed the castle with his retainers on the pretext of releasing Organtino and Lorenzo.  At this moment, he explained his decision and proceeded to cut his hair with a short sword.  Ahgast, his retainers stopped him, but after Ukon handed them his swords, ceremonial robe, and hair, he removed his clothes down to an undergarment, he headed with Organtino and Lorenzo to meet Nobunaga.

The remaining retainers returned to the castle and discussed whether it would be a good idea to have Tomoteru also surrender to Nobunaga and occupied every part of the castle.  During these events, Tomoteru was sleeping the entire time, but was shocked after being shown the letter left by Ukon and became enraged after seeing the main citadel where Ukon should have been and other parts of the castle were shutdown.  After a momentary act of rage, Tomoteru went to Arioka Castle and proposed that he be taken in lieu of the hostages and was permitted to do so.

On 11/16, Ukon went to Nobunaga to express his appreciation.  Nobunaga was pleased and awarded Ukon the short-sleeved kimono he was wearing, a horse, and the Settsu and Akutagawa districts as his territory.  In this way, Takase Castle was surrendered to Nobunaga’s army while Tomoteru and the hostages were not subject to execution.

Defending the castle

After Ukon, Nakagawa Kiyohide of Ibaraki Castle surrendered, while Ōwada, Tada, and Sanda castles all switched their allegiance to Nobunaga so Murashige was isolated.  Moreover, many soldiers from the Araki army fled so the size of the force went from between 10,000 to 15,000 down to 5,000 men.

At this point, Nobunaga viewed the war situation as favorable so he cut-off settlement negotiations with the Ishiyama-Hongan Temple.  On 11/14, an army led by Takigawa Kazumasu, Akechi Mitsuhide, Hachiya Yoritaka, Ujiie Naomasa, Andō Morinari, Inaba Yoshimichi, Hashiba Hideyoshi, and Hosokawa Fujitaka clashed with a vanguard unit from the army of Araki Murashige.

Thereafter, Nobunaga moved his main base to Koikeda (Ikeda Castle) across the Ina Rover from Arioka Castle, and then laid siege to Arioka.  Ikeda Castle was Murashige’s former base and, by this time, is considered to have been abandoned.  On 12/4, detached units from the Oda army led by Takigawa Kazumasu and Niwa Nagahide burned down Ichinodani in Hyōgo and established a camp in the environs of Tsukaguchi.  Attacks on the castle began in earnest around 6:00 PM on 12/8.  First, arquebus-wielding soldiers fired volleys into the castle, and, next, archers set fire to the residences in the town.  However, as was unusual in the Sengoku period, Arioka castle was protected by an outer wall to thwart an assault.  The attacks continued under darkness of night until around 10:00 PM, by which time the Oda had lost 2,000 soldiers including many senior retainers such as Mami Shigemoto.  Together with Hori Hidemasa and Sugaya Nagayori, Shigemoto commanded the infantry units.  While attempting to breach the stone walls, he was stabbed with a long sword.  One account noted that his actions would be remembered as those of a special bushō.

Thereafter, Nobunaga reinforced the positions around the castle and, on 12/11, returned the formation to Koikeda.  On 12/15, Nobunaga returned himself to Azuchi Castle.  In the authenticated account of Nobunaga known as the shinchō kōki, details regarding Arioka Castle diminish from this point, and instead discuss his activities such as his enjoyment of falconry.  Drawing from the action to burn down the town, it is surmised that Nobunaga adopted a plan for a war of attrition.  Owing to unexpectedly large losses incurred during the battle on 12/8, Nobunaga appeared to have changed the battle plan from a forceful assault on the castle to one focused on severing supply lines to the castle.  Arioka was a large castle occupying an area of 400 meters from east to west and 600 meters from north to south.  In addition to stone walls, Arioka was one of the first castles in Japan featuring a main citadel.  On the grounds stood the Kitano, the Jorōzuka, the Hiyodorizuka, the Kishino, and the Koyaguchi fortresses to defend the castle.  The defenders also added multiple lines of trenches and fences to resist attack.  Meanwhile, the Oda army set-up positions over a wide area from Arima to Yamazaki and prepared for a long siege.

Murashige expected reinforcements from the Mōri army or the Ishiyama-Hongan Temple army, but none arrived.  As the provisions dwindled, an effort was made to boost morale by launching a nighttime attack at the break of new year’s day in 1579 against the Kamo fortress occupied by a unit under Nobunaga’s eldest son, Oda Nobutada.  A total of 3,000 soldiers from Mino and Ōmi provinces led by Nobutada were located at the fortress.  Murashige himself commanded the attack by having 500 soldiers rush out of the Kitano fortress, setting fires to the west of the Kamo fortress located about 300 meters away and cutting their way forward.  Another unit lied in wait to the east of the Kamo fortress to push back and kill enemy soldiers fleeing the fortress.  Soldiers in the Toneyama fortress who learned of the surprise attack against Kamo fortress rushed to support Nobutada’s unit, but the horses and provisions had already been taken and the fortress had been burned down.  Nobutada escaped without injury but news about the strength of Araki Murashige traveled to Kyōto which was even turned into a popular musical verse called an imayō.  Thereafter, the Oda army became more vigilant while Nobunaga himself visited the area for troop inspections.  On 4/18, three soldiers who came out of the castle to fight were killed, but there were no other accounts until the ninth month, so details of the battle during that period are unknown.

In the middle of the night on 9/2, Murashige took five or six close associates, and, under the cover of darkness, traveled by boat down the Ina River.  They moved to the base of Murashige’s eldest son, Araki Muratsugu, at Amagasaki Castle (also known as Daimotsu Castle).

Similar to what appeared to occur at the Battle of Miki, the Mōri clan promised to send reinforcements but, other than supplying provisions via Hanakuma and Amagasaki castles, no support troops came even after one year.  As a result, Murashige may have determined that it would be impossible to hold out in the castle, and sending retainers as messengers would be futile, so he himself attempted to go to Aki to engage in direct negotiations with the Mōri.  He brought tea utensils as a gift to the Mōri.  Moreover, in addition to seeking support from the Mōri army, Murashige may have made a strategic decision to move to Amagasaki on the coastline to avoid the disadvantages of Arioka as an inland castle.

Murashige’s flight from Arioka was concealed for a while, but once Nobunaga’s spies found out, on 9/12, Nobunaga directed, under the command of Nobutada, a majority of the troops laying siege to Arioka toward Amagasaki while Takigawa Kazumasu commenced operations to lure opponents to their side.  Kazumasu used the fact that Murashige fled to solicit betrayal by the general in charge of defending the Jorōzuka fortress (Nakanishi Shinhachirō) and his vice general (Miyawaki Heishirō) and succeeded.  Kazumasa was known as a military stategist under the phrase “To go forward – Kazumasu; To go back – Kazumasu.”  Also skilled in assorted maneuvers, such as espionage or the solicitation of enemies to collude or betray their lords.  He was one of the preeminent bushō of his time.

Around 10:00 PM on 10/15, the Oda army initiated a full-scale attack against Arioka Castle.  The defenders quickly took-up positions in each of the fortresses and prepared for battle.  However, as Takigawa’s unit approached Jorōzuka fortress, they were able to enter the castle grounds without any resistance.  This was because not only did Nakanishi Shinhachirō and Miyawaki Heishirō betray the defenders, but the commander of foot soldiers was persuaded by Nakanishi and the others to betray was also involved.  Surrounded by an outer wall, Arioka was vulnerable to attack from within.  The defenders were killed en masse, the commander of Kitano fortress (Watanabe Kantarō) and the commander of Hiyodorizuka (Nomura Tango) both offered to surrender, but, after their offers were rejected, they committed seppuku.  Soldiers from the Saika group who came to support the defenders were not effective in close combat and almost completely eviscerated.

In a castle surrounded by an outer wall, many peasants and townspeople also had residences on the castle grounds.  The Oda army burned down the castle while fires spread from the neighborhoods of townspeople to the residences of samurai.  Non-combatants fled to the second outer citadel, but the Oda forces entered there so they pulled back to the innermost citadel.  This portion was surrounded by moats on three sides, while the southern side was separate from the second outer citadel by an empty moat so, finally, the Oda army could not enter the inner citadel.

On 11/19, Araki Kyūzaemon (later known as Ikeda Tomomasa), who was in charge of defending the castle, decided to open the castle, whereupon Tsuda Nobuzumi led a requisition unit into the inner citadel, drawing to a close the Siege of Arioka Castle.

Consequences of the battle

Araki Kyūzaemon decided to open the castle in response to an offer from Nobunaga such that if Murashige vacates Amagasaki and Hanakuma castles, Nobunaga would spare the lives of the family and their retainers located in the inner citadel of Arioka.  Kyūzaemon then led 300 soldiers to Amagasaki, but Murashige could not be persuaded to accept the offer.  According to one account, Murashige deliberated with priests from Ōsaka (associated with the Ishiyama-Hongan Temple), but the priests did not agree at all.  At this time, members of the Mōri clan, the Ishiyama-Hongan Temple, and guards from the Saika group were present at Amagasaki Castle, so Murashige’s opinion was no longer decisive.  Having promised to persuade Murashige to accept the offer, Kyūzaemon may have concluded that he could not face Nobunaga, so Kyūzaemon and 300 of his soldiers absconded from the castle.

Nobunaga regarded Murashige and Kyūzaemon (for breaking his promise) to be insincere and crafty persons, so although pitiable, determined the Araki not to be qualified as a military family, and ordered all hostages to be executed.  First, the Oda moved Murashige’s wife (second wife or consort) named Dashi along with other members of the Araki family and senior retainers totaling 36 people to the Myōken Temple in Kyōto; then around 9:00 AM on 12/13, the hostages from the inner citadel at Arioka were escorted to Nanatsumatsu were Nobutada had set-up a base near Amagasaki Castle.  The forces constructed 97 crosses (used in a crucifixion), dressed 122 women and children of retainers in clean clothes, and shot them with arquebuses.  After that, 124 men and 388 women were put into four farmhouses and burned alive when the houses were set on fire in tragic circumstances.  At the same time, the 36 people in the Myōken Temple were paraded around Kyōto and then taken to a site known as Rokujō-gawara where they were executed by beheading.  Those executed included the fourteen-year-old son of Kyūzaemon (Araki Jizen) and the twenty-year-old pregnant wife of Araki Hayato-no-suke.  Between both locations, a total of 670 persons were sacrificed.

Thereafter, Murashige slipped out of Amagasaki Castle in the middle of the twelfth month and moved to Hanakuma Castle.  This led to the Battle of Hanakuma Castle, and after losing, he went into exile under the protection of the Mōri.

Finally, the hostages of Takayama Ukon were returned to him.  Takayama Tomoteru was incarcerated in Echizen but was later pardoned.


The Siege of Arioka Castle was not simply a battle that occurred at Arioka Castle and its environs, it also took place in the Rokkō mountain range.

The Mōri clan continued to send military provisions but not a single soldier.  Initially, the goods were brought on land at Amagasaki Castle and sent to Arioka Castle.  However, after the construction of Oda fortresses, the supply route from Amagasaki was severed.  Goods were then first brought on land to Hanakuma Castle were temporarily kept at Kannōji and Jūrinji castles, along with the caverns of Takarazuka, and then transported at night to Arioka Castle by traversing Koyano.

In the era of Miyoshi Nagayoshi, Kannōji and Jūrinji castles served as outposts in support of Koshimizu Castle.  At the time of this conflict, Koshimizu Castle had been abandoned and served as a base in support of Arioka.  Meanwhile, Kannōji and Jūrinji were used as beacon fortresses by which smoke signals were sent to notify the defenders of the movements of the Oda army.  Whether to sever supply lines or crush these fortresses, Nobunaga sent forces toward the Rokkō mountain range and these sites with orders to search and kill without reservation.  After repeated raids, Kannōji and Jūrinji, along with other temples in the Rokkō mountains that served as supply bases were discovered and burned down.