The Rise of Massed Tactics in Japanese Warfare

It has been all too commonly assumed that guns triggered a tactical revolution in Japanese warfare, giving rise to “massed tactics”. That is, fighting in close quarters formation as a coherent group. But massed tactics were already being used in Japan well before the introduction of guns. In fact, it seems the transformation was triggered by pikes in the 15th century around the time of the Onin War.

So first, let us look at the prior history of the pike. Long polearms had been imported into Japan from the continent for the armies of the Ritsuryo state (the Chinese influenced centralized imperial system) in the 7th century. Once those armies began to break down as military force became privatized those polearms declined, though the shorter spear fared somewhat better. In the 14th century a weapon called the Kikuchi pike appears, an innovation of the Nambokucho Wars (a civil war on its face about the imperial succession, but somewhat more complicated than that). A Kikichi pike was a short blade attached to a long bamboo pole, and may have been related to a polearm used during Mongol Invasions. That weapon had been a knife mounted on a pole 5 feet in length, and can be found in the Scrolls of the Mongol Invasions commissioned by Takezaki Suenaga. In both cases the pike was the weapon of the lesser warrior, and may have functioned as the poor man’s replacement for the naginata, the Japanese curved halberd or glaive. They do not appear to have been effective weapons, as they account for only fifteen casualties known from battle reports made during the 14th century. By contrast swords of all types caused 92 percent of all documented nonprojectile casualties.

Once the samurai realized just how useful pikes could be when massed together in close formation and large numbers this changed. Doing so would require both cash and supplies, also leading to the creation of standing armies. The logistics were provided by a new tax created during the early years of the Ashikaga Shogunate. In 1352, the founding shogun, Takauji, introduced a new tax, the hanzei (half-tax) on eight provinces most affected by the Nambokucho Wars, and gradually expanded nationwide. The half tax allowed the Ashikaga’s military constables, the shugo, to use half of the revenue of their provinces for provisions and upkeep of their armed forces. Increased income and other powers exercised by the Shogunate and its officers made it more profitable for warriors to work with the system rather than against it. Most importantly for our purposes, the half tax allowed the shugo to amass the kind of logistical support base needed to train and maintain organized troops indefinitely.

We can already see this beginning long before the Onin War. In 1417-18 men from the province of Musashi organized into a Northern White Flag Corps (or possibly a Southern Corps). These two groups reveal that geographic origins had begun to mean more than kinship ties in warrior organization (demonstrating that organization had become more cohesive). The former corps also reveals that its men were identifying themselves with common insignia, in this case, a white cloth representing the Minamoto lineage. In the following decades, geographic organization became more frequent. In 1423 men from Musashi, Kozuke, and Shinano fought together as a cohesive group from central Japan. In the 1440s, generals were commanding troops out of a single region. Tactical changes were still not coming into force quite yet, as evidenced by battle reports.

For that, we turn to the succession struggle within the House of Hatakeyama. The Hatakeyama was one of the three leading cadet families of the Ashikaga, alongside the Hosokawa and Shiba and the theoretically shared the position of Deputy Shogun or Kanrei. They were also shugo in Kawachi, Kii, Noto, and Etchu and gained prominence from that. In 1450, Hatakeyama Mochikuni retired as family head but left the matter of his successor unclear. He had a son, Yoshinari but had given the boy up for holy orders while he was young. In the 1440s, he adopted a nephew, Masanaga and made him the heir. When Mochikuni retired, he attempted to pass the headship to Yoshinari, pulling him out of the monastery in contravention to the previous arrangement. Masanaga’s camp was enraged, but the Ashikaga ruled in favor of Yoshinari in 1454. Political bickering ran for months and the shogun, Ashikaga Yoshimasa, reversed his ruling. Open fighting broke out in the streets of Kyoto. By the next year, Masanaga was deposed a second time, and he fled to Kawachi.

File:Ashikaga Yoshimasa.jpg

Ashikaga Yoshimasa, the 8th Muromachi Shogun. By 日本語: 伝土佐光信 English: Attributed to Tosa Mitsunobu [Public domain], via Wikimedia Commons.

Here enters the figure of Hatakeyama Yasaburo. Widely unknown, Hatakeyama Yasaburo was the older brother by blood of Masanaga and commanded his brother’s troops at this stage of the war. At one point, Yasaburo and Yoshinari engaged in a clash described as an “exchange of pikes”, a phrase never before encountered. The phrase suggests a tactical innovation, with the battles in Kawachi and Kii being fought nearly exclusively with pikes. Later events would suggest Yasaburo had taken his pikemen and transformed them into a formation with the discipline to defeat cavalry on the open field. Hatakeyama Yasaburo died in 1459 after gaining pardons for the faction of Masanaga at court, leaving much about him and his battlefield accomplishments unknown.

The peace did not last long. In 1460, Shogun Yoshimasa revoked Yoshinari’s right of attendance and ordered him to vacate the Hatakeyama mansion. Supposedly angered by the gift of a withered tree, the Shogun changed sides in the succession dispute, again. Masanaga was placed back in power and given a commission to take down Yoshinari. By this time, the latter had fled back into the Hatakeyama lands of Kawachi and Kii. The fighting centered on the siege of Mt. Take, lasted until early 1463 when Yoshinari finally surrendered the mountain. He went into hiding, slinking between Kii and Yamato while Masanaga took up posts at shogunal court in 1464. All throughout the fighting the Hatakeyama used pike formations (exposing the provincial corps of 28 provinces to it in the process), and this would spill into the Onin War.

With the beginning of the Onin War, Japan descended into the longest period of civil war in its history. On the surface, the fighting was over a series of succession issues for family headship for several great families, such as the Hatakeyama and Shiba. But after 1465 an even more significant dispute arose: the succession of the Ashikaga House itself. The two greatest statesmen in the land, Hosokawa Katsumoto, and Yamana Sozen, already engaged in a fierce rivalry, supported the opposite sides. Previously Katsumoto and Sozen would on occasion join, such as in the Hatakeyama incident where both had backed Masanaga. Now they took all out positions against the other over the shogunal succession, Katsumoto for the Shogun’s dispossessed former heir and brother Yoshimi, Sozen for the infant Yoshihisa the Shogun’s son. Within this dispute, all others became polarized between Hosokawa and Yamana and no one could remain neutral.

We shall focus on the effects on this on the Hatakeyama dispute and how it directly leads to the outbreak of fighting. In the last days of 1466 Hatakeyama Yoshinari, long a wanderer, was allowed to return to Kyoto in triumph. Behind the scenes, Yamana Sozen had taken Yoshinari’s cause and pleaded his case with the Shogun’s wife, Tomiko. She procured pardon for Yoshinari, and fear of Yamana pushed her husband into dispossessing Hatakeyama Masanaga for the third time. Also, he was given a commission to take down Masanaga. Already bolstered by previous victories in the Shiba succession dispute, Sozen demanded Katsumoto abandon Masanaga.

Instead of complying, Katsumoto fortified his mansion and called up troops. Shogun Yoshimasa panicked and ordered both Hosokawa and Yamana to sit out the fighting between the Hatakeyama factions. The Hatakeyama were commanded to fight it out in the woods near the Goryo Shrine north of the city. In a sudden attack at dawn on the 18th day of the first month of 1467 (according to the Japanese lunar calendar), Yoshinari emerged victorious.

But this would not be the end of the matter. Hosokawa Katsumoto would not abandon Masanaga and eventually stopped attending at the shogunal court. Instead, he was fortifying his mansion, and those of the shugo aligned with him followed suit. Yamana Sozen and those shugo aligned with him did the same. By a quirk of geography, the mansions of Katsumoto’s faction was largely in the eastern wards of the capital and those of Sozen’s in the west. Thus, they became known as the Eastern and Western armies, respectively. Tensions ran high until the 26th day of the fifth month when Eastern troops set fire to the mansion of Isshiki Yoshinao, the only Western estate in the eastern wards of Kyoto. The Western army retaliated by setting fire to the few mansions of Eastern supporters in the western wards and the war was on.

File:Hosokawa Katsumoto.jpg

Hosokawa Katsumoto, the leader of the Eastern army. By 日本語: 不明 English: Unknown [Public domain], via Wikimedia Commons.

It did not take long for the fighting to come to a stalemate. The opposing factions and the shugo who supported them fought in the capital as neither could afford to leave their fortified positions and both feared leaving Kyoto. As that would cause them to be labeled an enemy of the court, a loss of legitimacy they could not survive. Also, the shugo were already funneling men and supplies from their provinces into their respective camps. The Shogun Yoshimasa, not grasping what was happening, insulated himself in his cultural pursuits and remained above the fray. Meanwhile, the two factions had burned much of Kyoto to give themselves room to maneuver, especially the cavalry. Not just shugo mansions, but the temples and the dwellings of aristocracy and common alike were destroyed. As the fighting continued the East and the West both struggled for position, with the Western army forcing the East into cramped quarters in the northeast quadrant. The reason was the ongoing struggle for control of the supply lines into the capital, which the Western army seemed to be winning. For example, the Western victory in the battle near the temple of Nanzenji around mid-late summer in southwestern Kyoto. They were aided significantly by the arrival in the eighth month of Ouchi Masahiro and Kono Michiyasu with some 20,000 troops, leading to the first documented use of pikes in the Onin War.

On September 13th Western forces, still operating in the southwest, attacked and burned the temple of Sanboin. Battle reports state that six members of the Kikkawa family sustained pike wounds. An additional four were wounded by pikes on the 2nd and 3rd days of the tenth month. While not all Kikkawa casualties were caused by pikes (arrows caused eight casualties, rocks five, swords one) the increase in pike related injuries is still significant. The battle at Sanboin witnessed as many pike wounds as the previous century. The Western commanders were oblivious to this and only saw a chance to break Eastern resistance. The following month the Western commanders made a mass offensive inside Kyoto proper, demolishing the temple complex of Shokokuji to make room for their cavalry.


The modern Shokokuji, Kyoto. By Chris Gladis [CC BY-ND 2.0 (] via Flickr.

Opposing them was 2,000 pikemen under Hatakeyama Masanaga. According to the Chronicle of Onin the Hatakeyama leader had decided to take the initiative and led his pike squads in close formation behind shields to charge the Western cavalry where Shokokuji had once stood. The attack was a success, with the cavalry (despite numbering some 6,000 men) unable to break the infantry line. They suffered 67 casualties before withdrawing. Hatakeyama Yoshinari was also active in the area, allowing the cavalry to retreat behind his pikemen and forcing Masanaga to himself withdraw.

Never before had Japanese infantry successfully withstood cavalry out in the open. The battle marked the end of the mobile warfare phase of the struggle for the capital, and from this point on what mattered was the ability to hold ground. The Eastern army took the lead in this regard, building a trench system along their front lines at the beginning of 1468. The Western army followed, suit and was not long before Kyoto resembled a WWI battlefield. Some trenches were over 9ft deep and 19ft wide with watchtowers ranging from 69-99ft in height dotting the landscape. Night raids by small squads of light infantry became the favored tactic.

Despite this, army size and the demand for weapons only increased. The provincial support bases of the shugo proved unable to keep up with the needs of the soldiers. Leading to the ironic situation in Kyoto in which the manufacturing centers of the south were spared the worst fighting to make more weapons and armor. Cavalry shifted to supply line attacks, village raids, and reconnoitering. The fight for control of the supply lines, which continued nearly the whole eleven years, was never decided decisively. One line for Katsumoto or Sozen always remained open, and always had enough to keep the East and West in the field.

At this point let us examine the battle reports again. In contrast to the battle reports noted earlier in this article after 1467, the sword declined in use in favor of the pike. Swords account for 20 percent of all nonprojectile casualties across the Sengoku while pikes start off at 74 percent nonprojectile casualties during the Onin War to 98 percent nonprojectile casualties by the battle of Sekigahara in 1600. As a testament to the changes in Japanese warfare the practice of submitting battle reports began to change as well. Troops stopped sending reports of where they had marched, arrival at camp, and so on. Casualty lists replaced reports of warrior movements. Advances in army organization had made such practices unnecessary as commanders now knew more about the location of their troops and armies increased in size.

The Onin War would continue until 1477 (at least the stage of fighting in the capital) when Ouchi Masahiro pulled out of Kyoto. During that time, Hosokawa Katsumoto and Yamana Sozen had both died without achieving a decisive victory in 1473. The dispute over the shogunal succession ceased to matter relatively quickly, and Yoshimasa stepped down to place Yoshihisa in power to little notice or fanfare the same year Katsumoto and Sozen died. Yoshimi, the other “contender” lived a life in semi-nomadic exile, having already been bounced between sides so many times he no longer cared. Fighting in Kyoto spilled out into the provinces after 1473, marking the beginning of the Sengoku.

An interesting postscript to our topic is the triumphs of Miyoshi Nagayoshi in the 16th century. This man, originally a deputy shugo under the Hosokawa, used massed tactics to accomplish one of the better-known examples of gekokujo (the low overcoming the high). This practice was born out of the Onin War, as the Ashikaga political and social order broke down, and subordinates overthrew those over them. Using 900 pikemen, Miyoshi Nagayoshi was able to defeat Hosokawa Harumoto, who was not only the shugo he served but the real power within the Ashikaga Shogunate, in 1549. That same year he expelled the Ashikaga shogun, Yoshiteru, and would not allow him to return until 1552. The Miyoshi later killed Yoshiteru shortly after Nagayoshi’s death. During his lifetime Miyoshi Nagayoshi had based his power solely on military might, stemming from the efficient use of massed infantry acting in cohesion.


Weapons & Fighting Techniques of the Samurai Warrior 1200-1877 AD by Thomas D. Conlan

The Onin War: History of Its Origins and Background With a Selective Translation of The Chronicle of Onin by H. Paul Varley

Warrior Rule in Japan edited by Marius B. Jansen

Samurai, Warfare, and the State in Early Medieval Japan by Karl F. Friday

The Three Provinces Alliance

In 1554, the greatest three powers on Japan’s Kanto plain, the Imagawa, Takeda, and Hojo, put aside their mutual hostility to focus on other matters outside the Kanto. This alliance made possible three events: First, it allowed the Imagawa to make their fateful advance on Kyoto. Second, it allowed the Takeda to focus on Shinano. Third, it allowed the Hojo room to deal with the Uesugi.

To understand this agreement, we must go back to 1536. In that year Imagawa Ujiteru, the Lord of Suruga, died suddenly and lacked any sons. His brothers, including several who were serving as priests in Buddhist temples, all fought to succeed him. The Takeda of Kai and the Hojo of Sagami both took an interest in this fight (which was called the Hanagura Incident) and backed the capable fifth brother. This man took the name Imagawa Yoshimoto on his victory in 1537. Yoshimoto then married the eldest daughter of the Takeda clan head Takeda Nobutora, turning previous diplomacy on its head.

The Imagawa and Hojo had been close allies for decades by this time, and the Hojo daimyo Hojo Ujitsuna took offense at this perceived snubbing. Yoshimoto also negotiated the marriage of Takeda Harunobu (the future Shingen) to a noblewoman of the Imperial Court (a daughter of Sanjo Kimiyori). This arrangement was a return-in-kind for the marriage of Harunobu’s sister. Thanks to Satomi aggression, the Hojo would not act on the Imagawa realignment until 1539 by seizing territory on the western bank of the Fuji River. At the same time affairs in Kai changed dramatically.

While a talented ruler, Takeda Nobutora was not popular. Now considered to have suffered from some form of mental instability, Nobutora was a harsh, intemperate man who governed according his arbitrary designs. His retainers tolerated this for as long as it benefited them and the clan. For all his faults, Nobutora had succeeded in rebuilding the fortunes of the Takeda and unified the province of Kai. However, in 1540 he pushed them over the edge by announcing the deposition of his eldest son in favor of a younger one, Nobushige.

This was unacceptable to the retainers and Nobushige alike, as the latter remained loyal to his brother. Imagawa Yoshimoto got wind of this and supported his brother-in-law, as potential instability in Kai was not in the best interest of Suruga. So Harunobu, his guardian Obu Toramasa, and other senior Takeda retainers, plotted the downfall of Nobutora. While the details of the coup are unclear by 1541 Takeda Nobutora was living in exile in Imagawa lands, at the expense of Yoshimoto and Harunobu was lord of Kai. Harunobu paid back the debt in part by supporting the Imagawa during the Kitsunebashi campaign against the Hojo in 1544. By that time, Ujitsuna had died and was succeeded by his brilliant son Ujiyasu.

489px-Ujiyasu_HojoHojo Ujiyasu of Sagami. See page for author [Public domain], via Wikimedia Commons.

Under new leadership, Takeda made significant inroads into Shinano. In 1542, Harunobu defeated a major alliance of Shinano lords at the battle of Sezawa. The Suwa, Kiso, and Tozawa (in a separate campaign) clans were all absorbed. The Takato followed in 1545, and it appeared the Takeda would conquer the province shortly. The situation changed in 1548 when the Murakami dealt the conquerors a bloody nose at Uehara. When the Murakami and their allies the Ogasawara had been pushed out of Shinano in 1552, they fled to Echigo and the shelter of Nagao Kagetora (the future Kenshin).

The Imagawa had similarly become preoccupied with Mikawa and Owari. Nominally under the control of the Matsudaira clan, Mikawa had fractured after the death of Matsudaira Kiyoyasu in 1536. The Matsudaira themselves were similarly divided. The chaos opened the way for the invasions of Oda Nobuhide of Owari. Nobuhide (the father of the famous Nobunaga) was a talented and aggressive commander. His aggression would earn him the nickname “Tiger of Owari”. Nobuhide began by taking the Matsudaira stronghold of Anjo in 1540 in a lightning invasion. This sent the young lord of the Matsudaira, Hirotada, to the Imagawa for support.

Yoshimoto moved to intervene and sent an army commanded by his uncle, the monk-general Taigen Sessai into Mikawa. The resulting struggle lasted most of the decade. Eventually Taigen Sessai was able to defeat Nobuhide at 2nd Azukizaka in 1548. The following year, Hirotada died. Control passed to the Imagawa through the future Tokugawa Ieyasu, a child. Oda Nobuhide then died in 1551, causing a civil war in Owari.

Meanwhile in the east, the Hojo contended against the Uesugi and Satomi. In 1545 Hojo Ujiyasu and his brother Tsunanari won one of the finest victories of the era at Kawagoe. Defeating the combined forces of the allied Uesugi branch families (the Ogigayatsu and Yamanouchi) and the eastern Ashikaga in the process. The Hojo went on the offensive, and within a few years the Ogigayatsu Uesugi had been eliminated, the eastern Ashikaga contained and rendered toothless, and the Yamanouchi Uesugi struggling in Kozuke.

In 1551, Ujiyasu took the Uesugi fortress of Hirai and evicted them from Kozuke. Uesugi Norimasa, Lord of the Yamanouchi, fled to Echigo. Nagao Kagetora soon proved to be a problem for the Hojo, leaving them unable to secure Kozuke. To counter the Nagao, the Hojo were forced to divide Kozuke with the Takeda. To the east, the Satomi continued to pester the Hojo, and Ujiyasu was hard pressed to do anything about them.

With all three lords now confronted by situations that required their attention to be elsewhere they decided to settle the matter of their shared border by diplomatic means. Such an agreement would not have been without precedent. In 1545, the Takeda had proposed a truce that allowed the Imagawa and the Hojo the breathing room needed to deal with concerns in Mikawa and at Kawagoe.

In 1554, Yoshimoto, Ujiyasu, and Harunobu all met at Zensho Temple under the watchful eyes of Taigen Sessai. At the monk’s insistence, a network of marriages was arranged. Hojo Ujiyasu would wed his daughter to the heir of the Imagawa and his heir in turn was married to Harunobu’s daughter. In 1552 a prior arrangement had seen the heir of the Takeda wed to Yoshimoto’s daughter. Sessai further negotiated a mutual cease-fire between the factions and vows made for mutual reinforcement and support. Thus settled, the Three Provinces (named for Kai, Sagami, and Suruga) Alliance allowed each clan to focus on affairs outside the Kanto.

The Imagawa turned their eyes on Owari. Nobuhide had been succeeded by his second son, Nobunaga, who was an unlikely choice in the eyes of the neighboring lords. Nobunaga in his youth put on an elaborate act conducting himself in the most shocking manner possible to traditional mores. The charade ended in 1553 when an elder retainer had committed suicide out of shame, and Nobunaga took on a more acceptable, though still eccentric, manner. Imagawa Yoshimoto laid plans to deal with the Oda as his ambitions for Kyoto grew, which was derailed by the death of Taigen Sessai in 1557. By this time, he had come to depend on the talents of a maturing Ieyasu, now known as Matsudaira Motoyasu. The Imagawa campaign for Owari started the following year in 1558 with the fall of Terabe Castle. It ended with the ambush at Okehazama, the death of Imagawa Yoshimoto, and the catapulting of Oda Nobunaga to national prominence in 1560.

800px-The_grave_of_Yoshimoto_Imagawa_in_OkehazamaThe Grave of Imagawa Yoshimoto of Suruga at Okehazama. By Lombroso (Photo taken by Lombroso) [Public domain], via Wikimedia Commons

Power then passed to Imagawa Ujizane, Yoshimoto’s heir. However, Ujizane was a weak and politically inept leader, and before long he had alienated many of his father’s retainers. Fatally, among those included was Matsudaira Motoyasu. The young lord of Mikawa broke away from Imagawa control in 1561 by tricking Ujizane into releasing the Matsudaira hostages in Suruga. With the Matsudaira gone, the Imagawa turned to the Asahina clan for support. Under their influence, Ujizane executed many of his retainers, and the Imagawa fell into decline.

The Takeda turned to greater ambitions. While his allies took care of their concerns, Harunobu could resume his march into Shinano. In 1553, the Murakami and Ogasawara returned in force with the support of Nagao Kagetora and the two forces clashed for the first time at Kawanakajima. Eventually, the two warlords would fight five times over that ground. The battle ended in a stalemate though technically the Takeda came away a little worse. In any event, Harunobu’s ambitions had been checked. Eventually, he would triumph by conquering Shinano in 1564, but it came at a price through the constant skirmishes at Kawanakajima, especially the pitched 4th battle in 1561. Shingen (he had taken that name in 1559 on entering the Buddhist priesthood) then turned to Kozuke and Hida, and military action there would occupy him for much of the decade.

Takeda_HarunobuTakeda Harunobu of Kai, AKA Shingen. By 日本語: 不明 English: Unknown [Public domain], via Wikimedia Commons.

Internal problems would also plague the Takeda during those years. In 1560, a plot led by Shingen’s cousin Katanuma Nobumoto was uncovered, resulting in the conspirator’s death. There was a second plot in 1565, this time led by Obu Toramasa and Shingen’s heir Yoshinobu. Toramasa was forced to commit suicide while Yoshinobu was confined to Toko Temple. Two years later he died under unclear circumstances; though it seems likely his father forced him to commit suicide. These events placed great strain on the Three Provinces Alliances, as Imagawa Ujizane did not take well to the news of his sister’s disgrace, and the Hojo supported him.

For the Hojo, the alliance proved less advantageous. Already checked in Kozuke by the Nagao and with the Satomi blocking his expansion further east, Hojo Ujiyasu was left with little option in where to expand. So he turned inward, refining and extending a line of castles and their networks of satellite castles that served to protect Odawara and the Hojo domains. In 1559-1560 events in Echigo saw the rebirth of the Uesugi when Uesugi Norimasa adopted Kagetora, who took to his new role and name (Uesugi Masatora) with vigor. He also assumed the title of Kanto Chancellor.

The Uesugi struck into Kozuke with the Satomi in 1560 and continued to push inwards through the following year. During this Ujiyasu stepped down as lord of the clan, passing the title to his son Ujimasa, but in reality the elder Hojo remained in control.

The Uesugi advance went up to the walls of Odawara itself and succeeded in burning the castle town, but they were turned back after two months by logistics problems and the Hojo defenders. However, Masatora was able to score a propaganda victory by visiting the Tsurugaoka Hachiman Shrine at Kamakura. There, he announced his assumption of the Uesugi patrimony and entered the Buddhist priesthood, taking the name Kenshin. From here on for the next eight years Hojo and Uesugi would clash across the Kanto, the conflict finally ending until 1569 when Ujiyasu arranged for his 7th son to be adopted by Kenshin. In the meantime, Ujiyasu triumphed in the 2nd Battle of Konodai in 1564 against the Satomi, and Hojo forces entered Shimosa and Kazusa. However, the Satomi were not entirely defeated, continuing the feud.

By 1568, it was clear the Three Provinces Alliance had collapsed. However, Shingen’s ambition was what finally broke it. That year Takeda Shingen negotiated a secret deal with Tokugawa Ieyasu (he had changed his name to this form in 1566, by petition to the Imperial Court) to divide the Imagawa domain between them. The Tokugawa would take Totomi, the Takeda would take Suruga. However, both men possessed great ambition and during the invasion Takeda troops attempted to conquer Totomi, and Ieyasu sheltered Ujizane after the latter agreed to cede his land to the Tokugawa.

At the same time, Hojo Ujiyasu was enraged by Shingen’s one-sided actions and launched an invasion of Suruga in an attempt to throw the Takeda out, commanded by Ujimasa. Shingen’s response was to attack Odawara Castle itself in 1569. However, the Takeda overextended, leaving Hojo castles to their rear intact, and were forced to leave after burning the castle town to the ground. During the retreat the Hojo attempted an ambush at Mimasetoge, fought off with heavy casualties to the Takeda. In 1570 Ujiyasu died, and Hojo Ujimasa maintained the war with the Shingen for another year before agreeing to peace. This effectively set the stage for the events of the next decade.

In conclusion by agreeing not to attack each other the Imagawa, Takeda, and Hojo made it possible for them to attend their ambitions without fear of destabilizing the Kanto. In the end, it all came up short. Imagawa Yoshimoto underestimated Oda Nobunaga and paid with his life, making the Oda ascendancy possible in the process. Both Takeda Shingen and Hojo Ujiyasu found themselves blocked by an enemy who proved to be their equal in Uesugi Kenshin, resulting in a bloody stalemate between all three. Ambition, which brought the alliance together, tore it apart.