
In 1440, Japan was in the Muromachi Period, the early phase of the violent Sengoku, or Warring States period, marked by frequent localized wars. To control territories, many castles were built. One local warrior capitalized on the strategically situated 85-meter-high Inuyama Hill, surrounded by the natural moat of the Kiso River, offering clear views of the Nobi Plain and the ancient lands of Owari (Western Aichi) and Mino (Gifu).
Almost a century later, in 1537, Oda Nobuyasu, grandfather of the great Oda Nobunaga, took the hill and fortress, also known as Hakutei Castle. Recognizing its strategic importance, the Oda clan constructed a larger, sturdier, and more elegant castle. This became the first castle owned outright by Oda Nobunaga, although he left his uncle as a caretaker while he engaged in further battles.
Inuyama Castle, classified as a Hirayama-jiro, is the oldest of Japan's 12 remaining original castles. Located in Aichi Prefecture, it may seem small compared to others like Nagoya or Osaka castles. Its stone walls stand just five meters high, with the tower itself a mere 19 meters on top of that. The total floor space of the defensive tower structure is around 699 square meters, comparable to Hikone Castle, which is quite large for its time.

Today, only the keep, the main watchtower, remains. The lord's living quarters once occupied the wide flat area along the lower slopes of the mountain, which was fortified with turrets, barracks, walled corridors, and related buildings. Inuyama had nine yagura watchtowers around its perimeter and two main gates, with six smaller gates protecting the Honmaru.
Unlike most castles that name their precincts Honmaru, Ni-no-Maru, San-no-Maru, etc., Inuyama Castle's five baileys were named after trees, with the Honmaru at the top, and the lower slopes consisting of the Sumi, Momi, Kiri, and Matsu kuruwa.
The castle's architectural beauty is evident both inside and out. The tower is a four-story Borogata-type keep, with entry via the smallest anakura (basement) of all the castles in Japan. Steep stairs, built to save space and hinder armored invaders, lead to the spacious first floor.

The keep appears to be square, yet the northeastern corner features the widest open angle of any keep in Japan, providing better views and increased firing range along the eastern flank. The first floor is divided into several rooms, including the Jodan-no-Ma, the lord's official audience chamber, which is rare to find in a tower keep. This room features hidden doors in the wall, behind which the lord's bodyguards or a private retreat could be found.
Wide corridors called Musha-Bashiri (warrior running corridors) around these central rooms allowed defenders ample space to move during an attack. The first-floor Musha-Bashiri has six places where sliding doors once stood, reflecting an old style seen in Oda Nobunaga's Azuchi and Toyotomi Hideyoshi's Osaka Castles. However, these doors would hinder warriors' movements, preventing them from running around the central area.
Climbing to the second floor, you find the armory where weapons and armor were stored. The third story features wide outer corridors for warriors, especially archers, to move freely. Above that, small balconies under triangular eaves (hafu) provide fine views of the river and mountains and serve as firing positions. The fourth floor is a wide chamber with a low balcony offering spectacular views of the surrounding area.

The mid-section karahafu decorative curved roofing element and extended yagura watchtower were added during the Naruse years.
Inuyama Castle saw significant action, notably during the Battle of Komaki-Nagakute in 1584 when Toyotomi Hideyoshi used it as a base against Tokugawa Ieyasu. In 1600, it was threatened during the Battle of Sekigahara. The night before the battle, daimyo Takenaka Shigekado defected to the Eastern forces, and Ishikawa Sadakiyo, the lord of Inuyama, made a secret deal with the Eastern forces, securing the castle's future.
After a succession of lords, Naruse Masanori took control in 1617, and the castle remained in the Naruse family for generations. In 1871, after the feudal system ended, many of the castle's outer walls and buildings were destroyed. The main keep survived but was damaged in the 1890 Great Nobi Earthquake. The former Lord Naruse undertook repairs, and in 1935, Inuyama Castle was designated a National Treasure. It remained in the Naruse family's care until 2004 when it was handed over to Inuyama City and a new overseeing foundation.
Inuyama Castle is a fine example of 16th-century castle architecture and a treasured symbol of Inuyama City.
See also
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Arato Castle

Arato Castle was built in 1524 by the Yamada clan under the orders of their overlord, Murakami, as a small mountain fort. Over time, it gained strategic importance and became a focal point in the conflict between two famous daimyō of the Sengoku period — Takeda Shingen and Murakami Yoshikiyo. This conflict turned the castle into one of the key fortifications in the struggle for control over Shinano Province.
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Tatsuno Castle

Tatsuno Castle is not a single fortification but rather a complex consisting of two parts: a mountain fortress located at the summit of Mount Keirozan and a flatland-mountain castle situated at its base. The mountain stronghold was built around 1499 by Akamatsu Murahide. During the Muromachi period, the Akamatsu clan was an influential family that, at the height of its power, controlled the provinces of Settsu, Harima, Bizen, and Mimasaka. Murahide’s ancestors were directly involved in the events of the Genkō War in the 14th century and in the subsequent establishment of the Ashikaga shogunate. However, by the 15th century, due to the process of gekokujō, the clan began to lose its position under pressure from rising families, including their former vassals—the Urakami and Bessho clans. In addition, the Akamatsu faced constant pressure from the Amago clan of Izumo Province.
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Takamatsu Castle

Takamatsu Castle was founded by Ikoma Chikamasa (1526–1603), who was appointed ruler of Takamatsu by Toyotomi Hideyoshi in 1587. The following year, Chikamasa began construction of the castle on the coast of the Inland Sea (Setonaikai), completing it by 1590.
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Sawayama Castle

During the Kamakura period, Sabo Tokitsuna, the sixth son of Sasaki Sadatsuna, built a fort on Mount Sawayama. This fort occupied a strategically important position because it allowed control over traffic along the important Tōsandō route, which was later known as Nakasendō. This road connected the capital, Kyoto, with the eastern regions of the country. Due to its location, the fortification held great military importance, and during periods of civil war it repeatedly became the site of fierce battles.
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Nadzima Castle

It is believed that the first structures on this site were built by Tachibana Akitoshi (?-1568), head of the Tachibana clan, a branch family of the Ōtomo clan, as auxiliary fortifications for Tachibanayama Castle. In 1587, Toyotomi Hideyoshi established control over the island of Kyushu and granted Chikuzen Province to Kobayakawa Takakage, one of the leading vassals of the Mori clan. Takakage began construction of a new castle on the site of the existing fortifications in 1588. The exact date of completion is unknown, but by the time the invasion of Korea began in 1592, the castle had already been finished, as records note that Toyotomi Hideyoshi stayed there overnight on his way to Hizen Nagoya Castle, which served as the headquarters of the invasion forces.
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Kubota Castle

The founder of the castle is considered to be Satake Yoshinobu (1570–1633). Yoshinobu was one of the six great generals of Toyotomi Hideyoshi. During the Odawara Campaign of 1590, he took part in the siege of Oshi Castle under the command of Ishida Mitsunari, with whom Yoshinobu developed a good relationship.
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Kavanhoe Castle

Kawanoe Castle is located on the small Wasi-yama hill near the port area of the Kawanoe district in the city of Shikokuchuo, occupying a central position along the northern coast of Shikoku Island. Kawanoe was also known as Butsuden Castle. The term “butsuden” in Japan refers to temple halls, and for this reason it is believed that a Buddhist temple once stood on the site before the castle was built. Due to its location at the junction of four provinces on Shikoku Island, Kawanoe held significant strategic importance and was repeatedly targeted by rival forces seeking military control over the region.
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Yokote Castle

The founder of the castle is considered to be the Onodera clan. The Onodera were originally a minor clan from Shimotsuke Province and served Minamoto no Yoritomo (1147–1199), the founder of the first shogunate. The Onodera distinguished themselves in battle against the Fujiwara clan of the Ōshū branch and were rewarded with lands around Yokote. Around the 14th century, the Onodera moved to Yokote as their permanent residence. Their original stronghold was Numadate Castle, but after a series of clashes with the powerful Nambu clan, they relocated their base to the site of present-day Yokote Castle. It was likely during this time that the first fortifications appeared at the castle.
