Battle of Kiyosu Castle or Battle of Kaizu (August 16, 1552 - April 20, 1554) was the first victory of the young

Oda Nobunaga was a Japanese ''daimyō'' and one of the leading figures of the Sengoku period. He is regarded as the first "Great Unifier" of Japan. Nobunaga was head of the very powerful Oda clan, and launched a war against other ''daimyō'' to unify ...

in his struggle to unite the province of Owari against his cousin,

Oda Nobutomo was a Japanese warlord during the Sengoku period. He was head of the Kiyosu Oda faction of the Oda clan, and ruled the four southern districts of Owari Province as ''shugodai''. After Oda Nobuhide died in 1551, Nobuhide's son Nobunaga was init ...

, deputy governor of northern Owari.

Background

At the time when the seventeen-year-old Oda Nobunaga inherited family estates (of the so-called Shibata branch of Oda family, though Shobata Castle, built before 1520 by his grandfather, was abandoned in 1538) in the southwestern part of

Owari Province was a province of Japan in the area that today forms the western half of Aichi Prefecture, including the modern city of Nagoya. The province was created in 646. Owari bordered on Mikawa, Mino, and Ise Provinces. Owari and Mino provinces were ...

(around

Nagoya Castle is a Japanese castle located in Nagoya, Japan. Nagoya Castle was constructed by the Owari Domain in 1612 during the Edo period on the site of an earlier castle of the Oda clan in the Sengoku period. Nagoya Castle was the heart of one of the ...

) in spring of 1552, the southern parts of the province were ruled by his cousins, Oda from

Kiyosu Castle is a Japanese castle located in Kiyosu, eastern Aichi Prefecture, Japan. It is noted for its association with the rise to power of the Sengoku period warlord, Oda Nobunaga. The kanji in the name of the castle was written as 清須城. The curren ...

, and the eastern parts of Owari were ruled by the powerful

Imagawa clan was a Japanese samurai clan that claimed descent from the Seiwa Genji by way of the Kawachi Genji. It was a branch of the Minamoto clan by the Ashikaga clan. Origins Ashikaga Kuniuji, grandson of Ashikaga Yoshiuji, established himself in the ...

, who at the time ruled the neighboring provinces of Mikawa, Totomi and Suruga, and their vassals, the

Matsudaira clan The was a Japanese samurai clan that descended from the Minamoto clan. It originated in and took its name from Matsudaira village, in Mikawa Province (modern-day Aichi Prefecture). During the Sengoku period, the chieftain of the main line of th ...

(later Tokugawa) from Mikawa.

First Battle

Immediately after the death of Nobunaga's father

Oda Nobuhide was a Japanese ''daimyō'' and magistrate of the Sengoku period known as "Tiger of Owari" and also the father of Oda Nobunaga the first "Great Unifier" of Japan. Nobuhide was a deputy ''shugo'' (Shugodai) of lower Owari Province and head of the ...

in spring of 1551, his cousin

, deputy governor (

shugodai were officials during feudal Japan. Shugodai were representatives of provincial shugo when the shugo could not exercise his power, being often away from his province. Unlike shugo, who were appointed from the central power, shugodai were locally ...

) of the southern Owari, attacked his domain and captured two forts, but was suppressed by Nobunaga and his uncle, Oda Nobumitsu, lord of Moriyama Castle. Together, they re-capture the forts and defeated Nobutomo's forces at the village of Kaizu (3 km from Kiyosu), killing more than 80 prominent samurai, and burned the outskirts of Kiyosu on August 16, 1552 (

Lunar calendar A lunar calendar is a calendar based on the monthly cycles of the Moon's phases (synodic months, lunations), in contrast to solar calendars, whose annual cycles are based only directly on the solar year. The most commonly used calendar, the Gre ...

Second Battle

Next year, on July 12, 1553,

executed the legal governor (

shugo , commonly translated as “(military) governor,” “protector,” or “constable,” was a title given to certain officials in feudal Japan. They were each appointed by the ''shōgun'' to oversee one or more of the provinces of Japan. The pos ...

) of the province, Shiba Yoshimune, who lived as a glorified hostage at his castle, for conspiring with Nobunaga. Such a brutal violation of the governor and

Shogun , officially , was the title of the military dictators of Japan during most of the period spanning from 1185 to 1868. Nominally appointed by the Emperor, shoguns were usually the de facto rulers of the country, though during part of the Kamakur ...

's authority (who was formally venerated by all Japanese daimyos at the time as their legal and ancestral lord) isolated Nobutomo from the former allies, and the governor's son Shiba Yoshikane managed to escape to Nobunaga in Nagoya. Nobunaga mobilized his forces and on the July 18th defeated Nobutomo under the walls of Kiyosu, mainly thanks to the unusually long spears (between 18 and 21 feet) of his

ashigaru were infantry employed by the samurai class of feudal Japan. The first known reference to ''ashigaru'' was in the 14th century, but it was during the Ashikaga shogunate (Muromachi period) that the use of ''ashigaru'' became prevalent by various ...

, which Nobunaga had designed himself. Retainers of Kiyosu suffered significant losses (more than 30 prominent samurai), but Nobunaga did not dare to attack the castle, so left it under a blockade, waiting for the opportunity to take it by cunning.

Third Battle

Fall of Kiyosu Castle

After defeating the powerful Imagawa clan in the Battle of Muraki (January 24, 1554), and liberating parts of southeastern Owari from their domination, Nobunaga gained a great reputation in Owari and got a free hand for the final showdown with Oda Nobutomo of Kiyosu. Having lost most of his vassals in the battles around the castle, Sakai Dozen, Nobutomo's chief adviser, offered Nobunaga's uncle Nobumitsu the position of provincial governor if he betrayed Nobunaga. Nobumitsu apparently agreed to betray Nobunaga, and with a group of warriors he was released in Kiyosu, but during the night his men opened the gates and the castle was conquered by storm (April 20). Oda Nobutomo was forced to commit seppuku, while Sakai Dozen managed to escape to the province of Suruga, finding refuge with Nobunaga's archenemy,

Imagawa Yoshimoto was a pre-eminent ''daimyō'' (feudal lord) in the Sengoku period Japan. Based in Suruga Province, he was known as . he was one of the three ''daimyōs'' that dominated the Tōkaidō region. He died in 1560 while marching to Kyoto to become ...

. Thus Nobunaga conquered Kiyosu Castle and became lord of the southern Owari: as a reward, his uncle Nobumitsu was given

and two eastern districts (out of four) of lower Owari, while Nobunaga moved to

as his new seat.

References

Literature

* * * * {{Cite book , last=Turnbull , first=Stephen R. , url=https://www.worldcat.org/oclc/50564411 , title=War in Japan 1467-1615 , date=2002 , publisher=Osprey , isbn=1-84176-480-9 , location=Oxford , pages=18 , oclc=50564411