
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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Wakayama Castle

Wakayama Castle was built in 1585, when Toyotomi Hideyoshi ordered his uterine brother, Hashiba (Toyotomi) Hidenaga, to construct a castle on the site of the recently captured Ota Castle. The purpose of this construction was to secure control over the likewise newly conquered Province of Kii. Following an already established tradition, Hidenaga entrusted the project to his castle-building expert, Todo Takatora. Takatora carefully inspected the future castle site, personally drew up several designs, created a model of the planned castle, and took part in the work of laying out the grounds (nawabari). For the construction he brought in more than 10,000 workers and completed the large-scale project within a single year, which was considered extremely fast by the standards of the time.
Toyama Castle

Toyama Castle is located almost in the very center of the former province of Etchū and is surrounded by a wide plain with a large number of rivers. The very first castle on the banks of the Jinzu River was built in 1543 by Jimbo Nagamoto. The Jimbo clan were vassals of the Hatakeyama clan and governed the western part of Etchū Province. The eastern part of the province belonged to their rivals, the Shiina clan, who were also Hatakeyama vassals. Beginning in the 15th century, the influence of the ancient Hatakeyama clan gradually weakened, and as a result, the Jimbo and the Shiina fought constant wars for control of the province. Meanwhile, the forces of the Ikkō-ikki movement periodically intervened, helping first one side and then the other.
Takada Castle

During the Sengoku period, the lands where Takada Castle would later be built were part of Echigo Province and were controlled by the Uesugi clan.
Kishiwada Castle

The celebrated 14th-century military commander Kusunoki Masashige (1294–1336), who owned extensive lands south of what is now the city of Osaka, ordered one of his vassals, Kishiwada Osamu, to build a fortified residence. This order was carried out around 1336. These fortifications became the first structures on the site of what would later become Kishiwada Castle. From the beginning, the castle stood in a strategically important location—roughly halfway between the cities of Wakayama and Osaka, south of the key port of Sakai. Because of this position, it changed hands several times during periods of warfare.
Kaminoyama Castle

Kamino-yama Castle stood at the center of an important logistics hub, in the middle of the Yonezawa Plain, which served as the gateway to the western part of the Tohoku region. Roads connecting the Aizu, Fukushima, and Yamagata areas intersected here.
Imabari Castle

Tōdō Takatora (1556–1630) served at different times as a vassal of several famous clans—Azai, Oda, Toyotomi, and Tokugawa. He took part in the Battle of Anegawa (1570), the Battle of Shizugatake (1583), the invasions of Kyushu and Korea, the Sekigahara campaign (1600), and the Siege of Osaka (1614–1615).
Iwakuni Castle

Kikkawa Hiroie (1561–1625) was the grandson of the famous daimyo Mori Motonari and a vassal of the Mori clan. Under Mori Terumoto, he fought in both Korean campaigns and took part in the defense of Ulsan Castle. During the Battle of Sekigahara, Hiroie stood with his 3,000-man force on the side of the Western Coalition; however, even before the battle began, he sent Tokugawa Ieyasu a secret message stating that he did not intend to fight Tokugawa’s troops. As a result of his inaction, 15,000 soldiers under Mori Hidemoto were also unable to enter the battle, since Hiroie blocked their path.
Gujo Hachiman Castle

Gujo Hachiman Castle is located on 350-meter Mount Hachiman, near the confluence of the Yoshidagawa and Kodaragava rivers, and not far from the Nagaragawa River. During the Sengoku period, this area was of great strategic importance: it stood at a key crossroads of routes connecting Mino Province in the south with the Sea of Japan in the north, and Hida Province in the east with Echizen Province in the west.
