Kiyosu Alliance (a military alliance formed between Nobunaga ODA and Ieyasu TOKUGAWA) (清洲同盟)

Kiyosu Alliance was a military alliance formed between Nobunaga ODA, a Sengoku daimyo (Japanese territorial lord in the Sengoku period [Period of Warring States]) of Owari Province, and Ieyasu TOKUGAWA, a sengoku daimyo of Mikawa Province. This alliance was also called Shokutoku Alliance after each family name ('shoku' is a way of reading of the first Chinese character of Oda and 'toku' is of Tokugawa), or Bisan Alliance after each territory ('bi' is a way of reading of the first Chinese character of Owari Province and 'san' is of Mikawa Province).

Development toward the Formation of the Alliance

According to a legend, when Yoshimoto IMAGAWA was defeated by Nobunaga ODA at the Battle of Okehazama in 1560, Ieyasu TOKUGAWA (those days, Motoyasu MATSUDAIRA) who had been following the Imagawa clan tried to execute seppuku (ritual suicide) in Daiju-ji Temple under Okazaki-jo Castle. Ieyasu, who was persuaded by the chief priest of the temple to live to build a peaceful world, gave up seppuku and tried to be independent from the Imagawa family. However, Ujizane IMAGAWA, the son of late Yoshimoto IMAGAWA of Mikawa no kami (Governor of Mikawa Province), was angry. In 1561 Ujizane ordered his vassal Shizuzane OHARA, who was jodai (vassal who manages the castle while the lord is not in the castle) of Yoshida-jo Castle (Mikawa Province), to kill the hostage from the Matsudaira (Tokugawa) side at the entrance of Ryunen-ji Temple located under the castle. According a theory, Shizuzane killed the hostage by way of transfix with a spear. Ieyasu who became all-out confrontation with the Imagawa family of east Suruga Province thought about approach to the child of west Nobuhide ODA, Nobunaga. In addition, Ieyasu might have thought that it was a wide policy to form an alliance with Nobunaga ODA of the neighboring province that has been expanding power with the tremendous momentum. Therefore, he sought the alliance with Nobunaga through Kazumasa ISHIKAWA, who was right hand of Ieyasu in those days, as a deal maker.

The other party Nobunaga also had an idea of forming an alliance with Ieyasu for reasons of his being at war with the Saito clan of Mino Province and his need to have a countermeasure to keep movements of Ujiyasu HOJO of Kanto region and Shingen TAKEDA of Kai Province in check; therefore, Nobunaga himself already had ordered Nobumoto MIZUNO, who was Ieyasu's maternal uncle, and others.

However, among the vassals of both families there existed a strong grudge because Nobuhide ODA (father of Nobunaga) and Hirotada MATSUDAIRA (father of Ieyasu) fought and were old enemy relation for each other, thus the alliance was not formed easily. It was after two years from the Battle of Okehazama that the alliance was formed officially. This alliance was called Kiyosu Alliance because, on this occasion, Ieyasu visited the Kiyosu-jo Castle where Nobunaga lived, to form the alliance after interviewing with Nobunaga.

From Alliance of Equals to Subordinate Alliance

Nobunaga and Ieyasu were the sworn allies at the beginning. In 1567 Nobunaga's daughter Tokuhime and Ieyasu's legitimate son Nobuyasu MATSUDAIRA married, and the relationships of the two were further deepened.

When Nobunaga ODA conformed to Yoshiaki ASHIKAGA strategically to visit the capital in Kyoto, Ieyasu dispatched reinforcement to Nobunaga for hunting down the Asakura clan, for the Battle of Anegawa, and so on. Nobunaga also dispatched reinforcement to Ieyasu for the battles against the Takeda clan at such battles as the Battle of Mikatagahara, the Battle of Nagashino, and so on. As previously described, their interest was in accord with each other; Nobunaga sought reinforcement from Ieyasu when he was in a critical situation by the anti-Nobunaga network of Shogun Yoshiaki; Ieyasu did from Nobunaga when he needed to win successfully through a fight with his powerful enemy Shingen TAKEDA.

However, the relation of Nobunaga and Ieyasu had begun to delicately change after Shingen died of an illness. Shingen died in 1573 and a menace of Takeda clan is reduced to half; with the death of Shingen there was no one who could fight with Nobunaga in equal terms in the world; in addition, anti-Nobunaga network collapsed, too. For this reason, Nobunaga was able to fight with Takeda clan in equal terms without forming the alliance with Ieyasu. After the death of Shingen, Nobunaga conquered provinces of various regions and other opposing power one after another including the Muromachi bakufu (Japanese feudal government headed by a shogun), the Azai clan, the Asakura clan, uprisings of Ikko sect of followers from Ise-Nagashima and Echizen Province; as the result, he expanded his power to provinces around the ancient capitals of Nara and Kyoto, Saigoku (western part of Japan [especially Kyushu, but ranging as far east as Kinki]) and Hokkoku (the north western part of the main island of Japan). When Kenshin UESUGI died in 1578, threats to Nobunaga were completely gone. By that time the territory of Nobunaga had become very large and included most of the Provinces around the ancient capitals of Nara and Kyoto, Hokuriku region (the northwestern part of the main island of Japan), Chugoku region (the westernmost region of the main island of Japan), Shikoku, and a part of Togoku (the eastern part of Japan, particularly Kanto region). While Ieyasu was only a small daimyo (Japanese feudal lord) who ruled only two provinces of Mikawa and Totomi Provinces, Nobunaga no longer needed power of Ieyasu as he already had the power to rule the entire Japan. This led the equal relationship of allies into formal one that Ieyasu become the virtual vassal of Nobunaga which Ieyasu accepted.

And, in 1579, Nobunaga asked Ieyasu to execute Nobuyasu MATSUDAIRA, the legitimate son of Ieyasu and Tsukiyama-dono, the biological mother of Nobuyasu. That's because Gotokuhime (Princess Toku) told Nobunaga that Nobuyasu and Tsukiyama-dono secretly communicated with Katsuyori TAKEDA; while Ieyasu, the Nobunaga's allies of sorts and the virtually dependent to the leader Oda, had no power neither to deny Nobunaga's order, nor to fight with him by abrogating the alliance, it is said that he had no choice but to execute Nobuyasu and Tsukiyama-dono (although the confrontation of Nobuyasu and Ieyasu, more precisely Nobuyasu and the vassals of Ieyasu was getting intense at this time, therefore, a theory is getting dominant in recent years which advocates that the purge of Nobuyasu was not Nobunaga's demand).

In 1582, an allied force of Nobunaga and Ieyasu invaded and attacked the territory of Takeda and destroyed Katsuyori TAKEDA in Mt. Tenmoku. In dividing former territory of the Takeda clan, Shinano Province was given to Nagayoshi MORI and the Hideyori MORI of vassals of Oda, the Kai Province to Hidetaka KAWAJIRI, the Kozuke Province to Kazumasu TAKIKAWA, and the Suruga Province to Ieyasu, respectively. However, the Suruga Province was given in a manner that Ieyasu went to Nobunaga in Azuchi-jo Castle then was granted by him. By this time, Ieyasu has fallen down to the position of a vassal under the leadership of Nobunaga although he was not treated as officials who deal with military affairs such as other commanding officers of Oda family or a local governor.

The End of the Alliance

When Honnoji Incident occurred and Nobunaga died a violent death in June, 1582, the alliance naturally ended. Right after the Honnoji Incident, it is often said that Ieyasu worked behind the scenes of Hidetaka KAWAJIRI's unusual death by a riot of a surviving retainer of the Takeda clan in Kai Province, and taking advantage of the death of Nobunaga, Ieyasu invading Kai and Shinano Provinces started a riot between the Hojo clan and the Uesugi clan who invaded the former territory of the Takeda clan with the same intention (Tenshojingo War).

After the death of Nobunaga, Hideyoshi HASHIBA, who defeated Katsuie SHIBATA, the head of retainers of Nobunaga, at the Battle of Shizugatake, rose in power, then Ieyasu dispatched reinforcement to Nobuo ODA, who called himself the successor of Nobunaga, in the Battle of Komaki and Nagakute (between Hideyoshi and Nobuo ODA) in 1584. However, Nobuo lacked the capability and talent of Nobunaga as his father; therefore, Ieyasu was rather on the dominant position in the relationship with Nobuo.

While the allied force of Nobuo and Ieyasu was superior in the battle, Nobuo whose territory of Ise and Iga Provinces were occupied by Hideyoshi succumbed to the condition of peace, then Ieyasu losing the cause of the battle had an audience with Hideyoshi at Osaka-jo Castle on December 7, 1586 to show Hideyoshi their subordinate-superior relationship since Kiyosu Alliance, under several situations including the division between Ieyasu's vassals, Kazumasa ISHIKAWA changing side of Hideyoshi, and conciliation by Hideyoshi himself.

Significance of the Alliance

In the Sengoku period when the word 'being faithful' meant almost piece of paper, it was exceptional that this alliance was kept for 20 years (even if taking into consideration that later 10 years was an alliance not of equals but of fully subordinate-superior relationship). Thanks to this alliance, Nobunaga could succeed going to the capital in Kyoto and expand his power to the western part of Japan without worry for the region he left behind. Meanwhile, prevented by strong enemies such as the Takeda clan and the Hojo clan, Ieyasu could not expand his power as much as he wanted, however, even in the difficult situation, his consistent and stubbornly honest attitude of being faithful and loyal to Nobunaga in the West raised his reputation tremendously within and beyond his territory, which is said to have helped him taking position in reigning the Japanese government (in the concrete terms to have Imperial Proclamation of seii taishogun [literally, "great general who subdues the barbarians"]). It can be said that this alliance had a decisive influence on the Japanese history later.

The Sources of the Terms

"Mikawa Monogatari" (Tales from Mikawa) by Okubo and "Shinchoko-ki" (Biography of Nobunaga ODA) by Gyuichi OTA do not contain descriptions of the Kiyosu Alliance; therefore, the quotation was taken from concluding the peace and amity with Nobunaga in "Mikawa Go Fudoki" (The Topographical Records of Mikawa Province). After the Battle of Okehazama, Nobumoto MIZUNO and Sadatoshi HISAMATSU often visited Ieyasu entering Okazaki-jo Castle as envoy of Oda family to persuade him as much as possible in words to become the daimyo of the Oda side, however, Ieyasu did not accept their words so easily then they said that following the stupid commander Ujizane who did not revenge for Yoshimoto died in battle would surely end up Ieyasu losing his territory by the Takeda clan and the Hojo clan. Hearing that major Nobunaga asking minor Ieyasu to follow was undeserved honor, Ieyasu made up his mind to exchange the peace document of oath each other in October 1961.