was a typical
hilltop castle. Originally conceived as fortresses for military defense, Japanese castles were placed in strategic locations, typically along trade routes, roads, and rivers. Though castles continued to be built with these considerations, for centuries, fortresses were also built as centres of governance. By the Sengoku period, they had come to serve as the homes of , to impress and to intimidate rivals not only with their defences but also with their sizes, architecture, and elegant interiors. In 1576,
Oda Nobunaga was among the first to build one of these palace-like castles:
Azuchi Castle was Japan's first castle to have a , and it inspired both
Toyotomi Hideyoshi's
Osaka Castle and
Tokugawa Ieyasu's
Edo Castle. Azuchi served as the governing center of Oda's territories, and as his lavish home, but it was also very keenly and strategically placed. A short distance away from the capital of Kyoto, which had long been a target of violence, Azuchi's carefully chosen location allowed it a great degree of control over the transportation and communication routes of Oda's enemies. The was used as a storehouse in times of peace and as a
fortified tower in times of war, and the 's government offices and residences were located in a group of single-story buildings near the
tenshu and the surrounding . The only exception was Oda Nobunaga's Azuchi-Momoyama Castle, where he lived in the . Before the
Sengoku period (roughly the 16th century), most castles were called . Though most later castles were built atop mountains or hills, these were built
from the mountains. Trees and other foliage were cleared, and the stone and dirt of the mountain itself was carved into rough fortifications. Ditches were dug, to present obstacles to attackers, as well as to allow boulders to be rolled down at attackers. Moats were created by diverting mountain streams. Buildings were made primarily of
wattle and daub, using thatched roofs, or, occasionally, wooden shingles. Small ports in the walls or planks could be used to deploy bows or fire guns from. The main weakness of this style was its general instability. Thatch caught fire even more easily than wood, and weather and soil erosion prevented structures from being particularly large or heavy. Eventually, stone bases began to be used, encasing the hilltop in a layer of fine pebbles, and then a layer of larger rocks over that, with no mortar. The character for castle or fortress (), up until sometime in the 9th century or later, was read (pronounced)
ki, as in this example,
mizuki. Though fairly basic in construction and appearance, these wooden and earthwork structures were designed to impress just as much as to function effectively against attack. Chinese and Korean architecture influenced the design of Japanese buildings, including fortifications, in this period. The remains or ruins of some of these fortresses, decidedly different from what would come later, can still be seen in certain parts of Kyūshū and
Tōhoku today.
Medieval period The
Heian period (794–1185) saw a shift from the need to defend the entire state from invaders to that of lords defending individual mansions or territories from one another. Though battles were still continually fought in the north-east portion of
Honshū (the
Tōhoku region) against native peoples, the
rise of the samurai warrior class towards the end of the period, and various disputes between noble families jostling for power and influence in the Imperial Court brought about further upgrades. The primary defensive concern in the archipelago was no longer native tribes or foreign invaders, but rather internal conflicts within Japan, between rival samurai clans or other increasingly large and powerful factions, and as a result, defensive strategies and attitudes were forced to change and adapt. As factions emerged and loyalties shifted, clans and factions that had helped the Imperial Court became enemies, and defensive networks were broken, or altered through the shifting of alliances. The
Genpei War (1180–1185) between the
Minamoto and
Taira clans, and the
Nanboku-chō Wars (1336–1392) between the Northern and Southern Imperial Courts are the primary conflicts that define these developments during what is sometimes called Japan's medieval period. Fortifications were still made almost entirely out of wood, and were based largely on earlier modes, and on Chinese and Korean examples. But they began to become larger, to incorporate more buildings, to accommodate larger armies, and to be conceived as more long-lasting structures. This mode of fortification, developed gradually from earlier modes and used throughout the wars of the
Heian period (770–1185), and deployed to help defend the shores of Kyūshū from the
Mongol invasions of the 13th century, reached its climax in the 1330s, during the Nanboku-chō period.
Chihaya Castle and
Akasaka castle, permanent castle complexes containing a number of buildings but no tall keep towers, and surrounded by wooden walls, were built by
Kusunoki Masashige to be as militarily effective as possible, within the technology and designs of the time. The
Ashikaga shogunate, established in the 1330s, had a tenuous grip on the archipelago, and maintained relative peace for over a century. Castle design and organization continued to develop under the Ashikaga shogunate, and throughout the Sengoku period. Castle complexes became fairly elaborate, containing a number of structures, some of which were quite complex internally, as they now served as residences, command centres, and a number of other purposes.
Sengoku ruins, destroyed during the
Siege of Katsurayama in March 1557|alt=A image of the Katsurayama Castle, destroyed during the Siege of Katsurayama in March 1557.|thumb The
Ōnin War, which broke out in 1467, marked the beginning of 147 years of widespread warfare (called the
Sengoku period) between
daimyōs (feudal lords) across the entire archipelago. For the duration of the Ōnin War (1467–1477), and into the Sengoku period, the entire city of Kyoto became a battlefield, and suffered extensive damage. Noble family mansions across the city became increasingly fortified over this ten-year period, and attempts were made to isolate the city as a whole from the marauding armies of samurai that dominated the landscape for over a century. As regional officials and others became the
daimyōs, and the country descended into war, they began to quickly add to their power bases, securing their primary residences, and constructing additional fortifications in tactically advantageous or important locations. Originally conceived as purely defensive (martial) structures, or as retirement bunkers where a lord could safely ride out periods of violence in his lands, over the course of the Sengoku period, many of these mountain castles developed into permanent residences, with elaborate exteriors and lavish interiors. The beginnings of the shapes and styles now considered to be the "classic" Japanese castle design emerged at this time, and
castle towns (
jōkamachi, "town below castle") also appeared and developed. Despite these developments, though, for most of the Sengoku period castles remained essentially larger, more complex versions of the simple wooden fortifications of centuries earlier. It was not until the last thirty years of the period of war that drastic changes would occur to bring about the emergence of the type of castle typified by
Himeji Castle and other surviving castles. This period of war culminated in the Azuchi–Momoyama period, the scene of numerous fierce battles, which saw the introduction of firearms and the development of tactics to employ or counter them.
Azuchi–Momoyama period Unlike in
Europe, where the advent of the
cannon spelled the end of the age of castles, Japanese castle-building was spurred, ironically, by the introduction of firearms. Cannon were rare in Japan due to the expense of obtaining them from foreigners, and the difficulty in casting such weapons themselves as the foundries used to make bronze temple bells were simply unsuited to the production of iron or steel cannon. The few cannon that were used were smaller and weaker than those used in European sieges, and many of them were in fact taken from European ships and remounted to serve on land; where the advent of cannon and other artillery brought an end to stone castles in Europe, wooden ones would remain in Japan for several centuries longer. A few castles boasted 'wall guns', but these are presumed to have been little more than large caliber arquebuses, lacking the power of a true cannon. When siege weapons were used in Japan, they were most often
trebuchets or catapults
in the Chinese style, and they were used as anti-personnel weapons.
Korea Toyotomi Hideyoshi's
invasions of Korea took place between 1592 and 1598, at the same time as the high point in Azuchi–Momoyama style castle construction within
Japan. Many Japanese castles (called
Wajō 倭城 in Japanese and
Waeseong in Korean) were built along the southern shores of
Korea. All that remains of these castles today are the stone bases.
Edo period in
Kyoto is attributed to
Kobori Enshū. model of the Edo Castle complex. The
Sengoku period, roughly a century and a half of war that brought great changes and developments in military tactics and equipment, as well as the emergence of the Azuchi-Momoyama style castle, was followed by the
Edo period, over two hundred and fifty years of peace, beginning around 1600–1615 and ending in 1868. Edo period castles, including survivors from the preceding Azuchi-Momoyama period, therefore no longer had defense against outside forces as their primary purpose. Rather, they served primarily as luxurious homes for the
daimyōs, their families and retainers, and to protect the
daimyō, and his power base, against peasant uprisings and other internal insurrections. The
Tokugawa shogunate, to forestall the amassing of power on the part of the
daimyōs, enforced a number of regulations limiting the number of castles to one per
han (feudal domain), with a few exceptions especially the ones in Satsuma and the ones up north , and a number of other policies including that of
sankin-kōtai. Though there were also, at times, restrictions on the size and furnishings of these castles, and although many
daimyōs grew quite poor later in the period, daimyō nevertheless sought as much as possible to use their castles as representations of their power and wealth. The general architectural style did not change much from more martial times, but the furnishings and indoor arrangements could be quite lavish. This restriction on the number of castles allowed each
han had profound effects not only politically, as intended, but socially, and in terms of the castles themselves. Where members of the samurai class had previously lived in or around the great number of castles sprinkling the landscape, they now became concentrated in the capitals of the
han and in
Edo; the resulting concentration of samurai in the cities, and their near-total absence from the countryside and from cities that were not feudal capitals (Kyoto and Osaka in particular) were important features of the social and cultural landscape of the Edo period. Meanwhile, the castles in the
han capitals inevitably expanded, not only to accommodate the increased number of samurai they now had to support, but also to represent the prestige and power of the
daimyō, now consolidated into a single castle. Edo castle, expanded by a factor of twenty between roughly 1600 and 1636 after becoming the shogunal seat. Though obviously something of an exception, the
shōgun not being a regular
daimyō, it nevertheless serves as a fine example of these developments. These vastly consolidated and expanded castles, and the great number of samurai living, by necessity, in and around them, thus led to an explosion in urban growth in 17th century Japan. As contact with Western powers increased in the middle of the 19th century, some castles such as
Goryōkaku in
Hokkaidō were turned once again to martial purposes. No longer needed to resist samurai cavalry charges, or arquebus squads, attempts were made to convert Goryōkaku, and a handful of other castles across the country, into defensible positions against the cannon of Western naval vessels.
Modern period in
Nagano Prefecture, a
National Treasure Meiji Restoration Before the feudal system could be completely overturned, castles played a role in the initial resistance to the Meiji Restoration. In January 1868, the
Boshin War broke out in
Kyoto, between samurai forces loyal to the disaffected
Bakufu government, and allied forces loyal to the new
Meiji Emperor, which consisted mainly of samurai and
rōnin from the
Choshu and
Satsuma domains. By January 31, the Bakufu army had retreated to
Osaka Castle in disarray and the
shōgun,
Tokugawa Yoshinobu had fled to
Edo (later Tokyo). Osaka Castle was surrendered to the Imperial forces without a fight, and on February 3, 1868, many of the buildings of Osaka Castle were burned. The heavy damage to Osaka Castle, which was a significant symbol of the power of the Shogun in western Japan, dealt a major blow to the prestige of the shogunate and the morale of their troops. From Edo, the Bakufu forces fled north to the
Aizu domain, from whence a large number of their troops hailed. As the
Aizu Campaign opened, Nagaoka and
Komine Castles were the scenes of heavy fighting. In the course of battle, Komine Castle was burned (it was re-built in 1994). The allied forces continued north to the city of
Wakamatsu, and lay siege to
Tsuruga Castle. After a month, with the walls and main tower pock-marked by bullets and cannonballs,
Tsuruga Castle was finally surrendered. Its buildings were later demolished or moved, with some of them being rebuilt starting in 1965. '' From Aizu, some Bakufu loyalists made their way north to the city of
Hakodate, on
Hokkaido. There they set up the
Republic of Ezo, centered on a government building within the walls of
Goryōkaku, a French-style
star fortress, which is nonetheless often included in lists and in literature on Japanese castles. After the fierce
Battle of Hakodate, the fortress of Goryōkaku was under siege, and finally surrendered on May 18, 1869, bringing an end to the Boshin War. All castles, along with the feudal domains themselves, were turned over to the
Meiji government in the 1871
abolition of the han system. During the
Meiji Restoration, these castles were viewed as symbols of the previous ruling elite, and nearly 2,000 castles were dismantled or destroyed. Others were simply abandoned and eventually fell into disrepair. Rebellions continued to break out during the first years of the Meiji period. The last and largest was the
Satsuma Rebellion (1877). After heated disagreements in the new Tokyo legislature, young former samurai of the Satsuma domain rashly decided to rebel against the new government, and lobbied
Saigō Takamori to lead them. Saigo reluctantly accepted and led Satsuma forces north from
Kagoshima city. Hostilities commenced on February 19, 1877, when the defenders of
Kumamoto Castle fired on the Satsuma troops. Fierce
hand to hand combat gave way to a siege, but by April 12, reinforcements of the Imperial army arrived to break the siege. After a series of battles, the Satsuma rebels were forced back to Kagoshima city. Fighting continued there, and the stones walls of
Kagoshima Castle still show the damage done by bullets. (Portions of the stone walls and the moat were left intact, and later the prefectural history museum was built on the castle's foundation.) The rebel force made their last stand on
Shiroyama, or "Castle Mountain", probably named for a castle built there some time in the past, whose name has been lost in history. During the final battle, Saigo was mortally wounded, and the last forty rebels charged the Imperial troops and were cut down by
Gatling guns. The Satsuma Rebellion came to an end at the
Battle of "Castle Mountain" on the morning of September 25, 1877.
Imperial Japanese Army Some castles, especially the larger ones, were used by the
Imperial Japanese Army. Osaka Castle served as the headquarters for the
4th Infantry Division, until public funds paid for the construction of a new headquarters building within the castle grounds and a short distance from the main tower, so that the castle could be enjoyed by the citizens and visitors of Osaka.
Hiroshima Castle served as
Imperial General Headquarters during the
First Sino-Japanese War (1894–1895) and later as the headquarters for the
5th Infantry Division;
Kanazawa Castle served as HQ for the 9th Infantry Division. For this reason, and as a way to strike against the morale and culture of the Japanese people, many castles were
intentionally bombed during World War II. The main towers of the castles at
Nagoya,
Okayama,
Fukuyama,
Wakayama,
Ōgaki, among others, were all destroyed during air raids. Hiroshima Castle is notable for having been destroyed in the
atomic bomb blast on August 6, 1945. It was also on the grounds of Hiroshima Castle that news of the atomic bombing was first transmitted to Tokyo. When the atomic bomb detonated, a team of volunteer high school girls had just taken their shift on a radio in a small fortified bunker in the main courtyard of Hiroshima Castle. The girls transmitted the message that the city had been destroyed, to the confused disbelief of the officers receiving the message in Tokyo.
Shuri Castle (actually a
Ryukyuan
gusuku), on
Okinawa Island was not only the headquarters for the
32nd Army and the defense of
Okinawa, but also has the distinction of the being the last castle in Japan attacked by an invading force. In April 1945, Shuri Castle was the coordinating point for a line of outposts and defensive positions known as the "Shuri Line". US Soldiers and Marines encountered fierce resistance and
hand-to-hand combat all along the Shuri Line. Starting on May 25, the castle was subjected to three days of intense
naval bombardment from the
USS Mississippi. On May 28, a company of
US Marines took the castle, finding that the intensity of the destruction had prompted the headquarters contingent to abandon the castle and link up with scattered units and continue the defense of the island. On May 30, the US flag was raised over one of the
parapets of the castle. Shuri Castle was re-built in 1992, and is now an
UNESCO World Heritage Site. Over of the Shuri Castle were burnt down due to an electrical fault on 30 October 2019 at around 2.34 am.
Reconstruction and conservation During the early 20th century, a new movement for the preservation of heritage grew. The first law for the preservation of sites of historical or cultural significance was enacted in 1919, and was followed ten years later by the 1929 National Treasure Preservation Law. With the enactment of these laws, local governments had an obligation to prevent any further destruction, and they had some of the funds and resources of the national government to improve on these historically significant sites. By the 1920s,
nationalism was on the rise, and a new pride was found in the castles, which became symbols of Japan's warrior traditions. With new advances in construction, some of the previously destroyed castle buildings were re-built quickly and cheaply with
steel-reinforced concrete, such as the main tower of
Osaka Castle, which was first re-built in 1928. While many of the remaining castles in Japan are reconstructions or a mix of reconstructed and historical buildings, and many of the reconstructed buildings are steel-reinforced concrete replicas, there has been a movement toward traditional methods of construction.
Kanazawa Castle is a remarkable example of a modern reproduction using a significant degree of traditional construction materials and techniques. Modern construction materials at Kanazawa Castle are minimal, discreet, and are primarily in place to ensure stability, safety concerns, and accessibility. At present, there are local non-profit associations that are attempting to collect funds and donations for the historically accurate re-construction of the main towers at
Takamatsu Castle on
Shikoku, and
Edo Castle in
Tokyo. There are only twelve castles with main keeps that are considered "extant" (Japanese 'genson'), although many other castles have significant numbers of other extant historical castle buildings: Most of these belong to or are maintained by local municipal governments. Some have been incorporated into public parks, such as the ruins of Kuwana Castle and
Matsuzaka Castle in
Mie Prefecture, Kunohe Castle (
Ninohe,
Iwate Prefecture), or
Sunpu Castle (
Shizuoka City). Others have been left in more natural state, often with a marked hiking trail, such as
Azaka Castle, (
Matsuzaka, Mie Prefecture), Kame Castle (
Inawashiro, Fukushima Prefecture), Kikoe Castle (Kagoshima city), or Kanegasaki Castle (
Tsuruga city,
Fukui Prefecture). The grounds of some were developed with municipal buildings or schools. In
Toba, Mie Prefecture, the city hall and an elementary school were built on the site of Toba Castle. Some castle sites are now in the hands of private landowners, and the area has been developed. Vegetable plots now occupy the site of Kaminogo Castle (
Gamagōri, Aichi), and a
chestnut orchard has been planted on the site of
Nishikawa Castle, though in both cases some of the castle-related topography can still be seen, such as the
motte or
ramparts. Finally there are the castle sites that have not been maintained or developed to any degree, and may have few markings or signs. Historical significance and local interest are too low to warrant additional costs. This includes Nagasawa Castle (
Toyokawa, Aichi), Sakyoden Castle (Toyohashi, Aichi), Taka Castle (Matsuzaka, Mie), and Kuniyoshi Castle (
Mihama,
Fukui Prefecture). Castle sites of this type also include nearly every area marked "Castle Mountain" (
Shiroyama) on the maps of towns and cities across Japan. Because the castle was small or may have been used for a short time in centuries past, the name of the castle is often lost to history, such as the "Shiroyama" at
Sekigahara,
Gifu Prefecture, or the "Shiroyama" between
Lake Shōji and
Lake Motosu near
Mount Fuji,
Yamanashi Prefecture. In such cases, locals might not be aware there ever was a castle, believing that the name of the mountain is "just a name". Detailed city maps will often have such sites marked. At the site, castle-related landscaping, such as ramparts, partly filled wells, and a leveled hilltop or a series of terraces, will provide evidence of the original layout of the castle. Whether their buildings are historical or reconstructions or a mix of the two, numerous castles across Japan serve as history and folk museums, as points of pride for local people, and as tangible structures reflecting Japanese history and heritage. ==Architecture and defenses==