Komaki Castle, properly known as Komakiyama Castle, was constructed in 1563 during the warlord Oda Nobunaga’s expansionist efforts. His goal was to defeat the neighboring warlord, Saito Tatsuoki, and take the province of Mino (now Gifu Prefecture). Oda Nobunaga, a military genius, recognized the importance of relocating to key strategic positions to expand his territories. For over ten years, Nobunaga had been based at the strategically important Kiyosu Castle in modern-day Aichi Prefecture. With his sights set on Mino, he chose to move his base of operations to a more northerly location.
According to legend, Nobunaga foresaw that his generals would resist relocating far from their established homes around Kiyosu. To address this, he first suggested building the new castle atop the distant and very steep 293-meter-high Mt. Ninomiya near Inuyama. As expected, his men balked at the idea, so he proposed the closer, lower, and more convenient Mt. Komaki instead. Unable to refuse their lord a second time, they agreed on Komaki.
The position of Komaki was ideal. Situated on top of an 86-meter-high hill, it provided an unhindered view across the vast Nobi Plain and surrounding areas, and it was surrounded by a small river that supplied water. Its proximity to Mino would also serve to psychologically unsettle the enemy.
Although Nobunaga only used the castle for four years, it appears he had intended to be based in Komaki much longer. The castle was very well designed, with many innovative features. It served as a template for Nobunaga’s most superb castle at Azuchi, constructed 13 years later. The designs and layout of both castles show many similarities. Recent research and excavations have revealed that Komaki was one of the earliest castles to extensively use defensive stonework, a feature that later became standard in all castles.
Of particular note were the large rocks stacked in three concentric rows around the top of the mountain. The upper ring surrounding the central bailey stood 3-4 meters high, while the middle and lowest rings were both about 2 meters high. One large rock weighing 190 kg was found with the name "Sakuma" written in sumi ink, believed to be that of an Oda samurai tasked with constructing the castle walls. This is the oldest known marking on an ishigaki (stone wall). Since that discovery, all stones unearthed at the site have been carefully washed and inspected for more brush marks.
Aside from the stone walls, the castle featured a 5.5-meter-wide Otemichi, a main path leading straight up the mountain. Nobunaga positioned the homes of his top retainers along either side of this path, ensuring that all his men were central to his needs. This feature was also seen at Azuchi years later.
Komaki was also Japan's first castle to feature a specially constructed Jokamachi (castle town) laid out below it. Partially defended by surrounding moats and 2-meter-high earthen walls, the town was laid out in a grid-like pattern south of the mountain. Nobunaga’s palace is believed to have stood on the flat, moat-protected precincts east of the mountain fortress. Interestingly, the layout of the castle grounds and the castle town was used again when Nobunaga built Azuchi Castle, although on a much larger and more elegant scale. Komaki was the trial, Azuchi was the perfected version.
Komaki Castle was abandoned in 1567 when Nobunaga ousted the Saito clan from what would be renamed Gifu Castle, establishing it as his new base of operations. Seventeen years later, thousands of samurai returned to Komaki for the Battle of Komaki and Nagakute. Komaki Castle didn’t see action until two years after Nobunaga’s death, when it became one of the sites of the Battle of Komaki and Nagakute in 1584. This historically important conflict initially began as a siege between the forces of Toyotomi Hideyoshi, Nobunaga’s general and successor, and Tokugawa Ieyasu, his former ally. Ieyasu set his war camp on the long-abandoned Komaki Castle site. The conflict later escalated into a full-blown battle in the Nagakute region.
The 21 hectares of tree-covered mountain are preserved as a National Historical Site. The three-story keep on top of Mt. Komaki is a 1968 concrete reconstruction, which never existed during the time of Nobunaga or Ieyasu. Although there is little information, the keep houses some interesting relics and an easy-to-understand diorama of the Battle of Komaki and Nagakute. Ongoing research means that archaeological digs are often taking place, and new gates, paths, stone walls, and details are continually being discovered at the innovative Komakiyama Castle.
See also
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Yoshida Castle
Yoshida Castle is renowned worldwide, particularly through the intricate woodblock prints by Edo Period artist Hiroshige. His famous series, depicting the 53 stages of the Tokaido—the historic route between Kyoto and Edo (modern-day Tokyo)—includes the 34th print, which shows workmen repairing a castle overlooking a wooden bridge crossing a wide river. This scene captures the Toyokawa River at Toyohashi in southeast Aichi Prefecture, and the castle is Yoshida Castle.
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Yamato Koriyama Castle
The impressive ruins of Koriyama Castle sit atop a small hill, surrounded by two rivers. The strategic positioning and strong layout of the castle served it well through the final years of the Sengoku period and the peaceful days of the Edo period.
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Yamanaka Castle
Yamanaka Castle, established by Hojo Ujiyasu in the 1560s, is located in what is now eastern Mishima, Shizuoka Prefecture. This castle served as the first line of western defense for the main Hojo Castle at Odawara. Carved into the side of a 586-meter-high mountain, Yamanaka Castle was strategically positioned along the Tokaido Highway, offering superb views of nearby Mt. Fuji, the ocean, and the road leading to Odawara.
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Uwajima Castle
Uwajima Castle, located in Uwajima City, Ehime Prefecture, Shikoku, is one of the 12 remaining Japanese castles with an original keep. Known for its small size, Uwajima Castle is relatively difficult to access, which means it is less frequented by tourists.
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Ueda Castle
Ueda Castle in Nagano Prefecture once stood prominently on a cliff overlooking the Saigawa River. Also known as Amagafuchi-Jo, Isesaki-Jo, Matsuo-Jo, and Sanada-Jo, it was built around 1583 by its first master, Sanada Masayuki. This sturdy yet small fortress cleverly utilized the surrounding natural defenses, including the river, steep rocky cliffs, the layout of the town below, and the strategically designed waterways to hinder attackers. Ueda Castle was fortified with seven defensive yagura (watchtowers) atop robust stone walls and had two large gates with watchtowers above them.
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Tsuyama Castle
Tsuyama Castle, located in Tsuyama City, Okayama Prefecture, is celebrated as one of Japan's top three major hilltop (Hirayama) castles, alongside Himeji and Matsuyama Castles. Originally, Tsuyama Castle comprised 77 structures, including the main keep, various yagura (watchtowers), gates, palaces, and living quarters. For comparison, Hiroshima Castle had 76 structures, and Himeji had 61. The first castle on this site was built in 1441 but was soon abandoned. The large-scale construction that we recognize today began in 1603 under the orders of Mori Tadamasa. The castle served as the administrative base for the Tsuyama Han daimyo, the Mori clan from 1603 to 1697, and the Matsudaira clan from 1698 to 1871.
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Tsu Castle
Tsu Castle, located in Tsu City, Mie Prefecture, was originally built by Hosono Fujiatsu in 1558 and was known as Anotsu Castle, named after the old region. The site was strategically chosen at the confluence of the Ano and Iwata Rivers, which naturally formed a moat around the castle, while the nearby port served as a vital trade route.
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Sasayama Castle
Tamba Sasayama Castle, also known as Sasayama or Kirigajo (Mist Castle), is a flatland castle (hira-jiro) situated on a gentle rise in the Tamba region of Hyogo Prefecture. It was constructed in 1608 as part of Tokugawa Ieyasu's strategy to prepare for an attack on Osaka, aiming to bring an end to the Toyotomi clan. Ieyasu ordered the castle's construction using the Tenka Bushin system, engaging 20 former enemy daimyo and their forces to complete the complex within six months. This system kept the former enemies close and preoccupied, financially straining them and limiting their capacity for further conflict. The stones used in Sasayama Castle feature engravings called kokumon, indicating who made each part of the walls and preventing theft by other lords' men.
