The operational history of Japanese castles is the story of the conflict and interplay between constantly improving methods of assault and new means of defence to counter them. This can be seen as siege warfare moves from crossbows against wooden towers, through traction trebuchets against the yamashiro complex, via stone-cladding and keeps, to the artillery bombardment at Osaka in 1615. Throughout samurai history the castle played a key role in warfare, and between 1570 and 1615 the theory that lay behind Japanese stone castles was tested to destruction.
An example of an early yamashiro under siege is Hiuchi in 1183, defended by a moat created by a dam, which the attackers broke. Later in the same year a hirajiro called Fukuryuji, defended by a Taira supporter, was attacked by Imai Kanehira. The attack was an infantry assault under fire from bows and arrows. The famous Ichinotani was a stockade hirajiro with one side on the beach, which Minamoto Yoshitsune attacked from the rear in 1184 down a steep cliff. The year 1189 is the last date in which we read of crossbows being used in Japan.
The best accounts of early yamashiro warfare refer to the Nanbokucho Wars of the 14th century, when Emperor Go Daigo attempted to reassert imperial power against the shogun. His revolt ended in failure, but was accompanied by much fighting in the mountains around Yoshino, where yamashiro provided bases. There are many accounts in the Taiheiki of surprise attacks by night, the use of dummy troops, collapsible bridges and the like.
With the beginning of the Sengoku Period we note numerous sieges against the pre-stone model of sengoku yamashiro. Arai was taken by the Hojo in 1516 after a desperate fight to control the drawbridge which connected the two halves of this island fortress. It was during the siege of Un no uchi in 1536 that Takeda Shingen, then aged 15, had his first combat experience, taking the garrison by surprise after marching through thick snow. The following year the Hojo besieged the Uesugi castle of Musashi-Matsuyama, when the garrison tried to summon help from outside by sending a message through the siege lines attached to the collar of a dog. Psychological pressures on a garrison may be noted at the siege of Shika in 1547, where Takeda Shingen had the freshly severed heads of the victims of the battle of Odaihara displayed in front of the castle walls. In each of these cases we may envisage a castle layout similar to that shown on page 11, with carved hillsides, ditches and palisades.
Two years later, far away in the south of Japan, Kajiki castle was captured by samurai of the Shimazu using the newly acquired Portuguese arquebuses, a weapon that was to revolutionise Japanese warfare. When Oda Nobunaga attacked Muraki castle in 1554 he used a system of rotating volleys of arquebus fire from just across the moat, a pattern that was to become very common in Japanese siege warfare, and was used to tremendous effect from field fortifications at the famous battle of Nagashino in 1575. But even the new arquebuses were not infallible, and the castle of Moji, which occupied a prominent vantage point overlooking the straits of Shimonoseki, changed hands five times between 1557 and 1561 in spite of gunfire, amphibious assault and even a bombardment from Portuguese ships. This was a unique event in Japanese history, and so dramatic was the illustration of the devastating effects of cannon-balls against a predominantly wooden fortress that it is surprising that there was so little future development in this direction. The castle of Musashi-Matsuyama enters the story again in 1563 when Takeda Shingen used miners to collapse its walls. In 1564 Inabayama fell, but only as a result of a classic infantry assault up its steep hill.
The attack on Fushimi castle, 1600
This plate shows the epic defence of the castle of Fushimi in 1600 by Torii Mototada, the loyal old retainer of Tokugawa Ieyasu. The siege lasted 11 days, and was important because its stubborn defence inflicted great losses on the army of Ishida Mitsunari that was afterwards to fight at Sekigahara. We see the Torii banners, bearing a torii (Shinto gateway) flying proudly from the walls. Inside the corner towers ashigaru keep up a series of arquebus shots while comrades try to douse the flames and other drop stones through trapdoors on to the samurai clambering up the stone base. Fire is returned by the troops across the moat sheltering behind wood and bamboo barricades where the general Kobayakawa Hideaki commands from his white horse. A cutaway shows the progress of a deep mine that will take the attackers underneath the wet moat. Labourers form a line to carry soil away on their backs and load it on to carts. In the foreground the leader of packhorses has arrived with supplies. Meanwhile to the left one of the outer towers has fallen and is now being used to press home the attack. In the end Fushimi only fell when a traitor, whose family had been taken hostage and were threatened with crucifixion, set fire to a tower and broke down a section of the wall. Torii Mototada committed suicide.
The beautiful keep of Himeji castle seen among cherry blossom. Himeji is the most visited castle in Japan.
Stone bases begin to play a part in castle warfare from about 1570 onwards. For the up-and-coming Oda Nobunaga, the decade was dominated by Japan’s longest siege when he spent ten years, on and off, reducing the Ikko-ikki’s formidable fortress cathedral of Ishiyama Honganji. This was a long and bitter campaign directed against a massive hirajiro complex of the latest style situated within a maze of reed beds and creeks. Supplies were run to them by sea courtesy of the Mori family, and the Ikko-ikki also had large numbers of arquebuses. Their satellite fortress of Nagashima also held out for years, and on one occasion an attacking army was caught by flooding from a broken dyke in a neat reversal of the conventional siege situation.
Midway through the Ishiyama Honganji operation there occurred the celebrated siege of Nagashino castle, which withstood several ingenious attempts to capture it, and was eventually relieved by the famous victory at the battle of Nagashino. This involved the mass use of arquebuses firing from behind field fortifications, and although the precise situation of Nagashino was never repeated, its influence can be seen in the temporary earthworks raised by both sides during the Komaki campaign of 1584. The result was stalemate, as neither side wished to repeat the mistake of Nagashino, and in fact the battle of Nagakute was fought several miles from the Komaki lines as much as a result of boredom as anything else. The ‘trench system’ of Komaki was never seen again in Japanese history as it just did not fit in with the samurai ethos, and the only use of earthworks in future was to augment a castle’s stone walls.
Yet every new siege made fresh demands upon the ingenuity of both besiegers and besieged, and the early 1580s saw two very different actions against castles. In 1581 at Tottori, a yamashiro with formidable stone walls, the weapon of starvation was used on an unprecedented scale. Kikkawa Tsuneie held out for 200 days, and surrendered only to save his men from having to eat each other. At Shizugatake in 1583, however, the situation was totally different. Shizugatake was one of a chain of sengoku yamashiro raised north of Lake Biwa by Toyotomi Hideyoshi to protect his communications with Kyoto. Little stone was used, and the means of attack adopted by Shibata Katsuie shows a very good understanding of the layout of a sengoku yamashiro complex, because instead of making a frontal assault on the most forward of the castles, he made his way along the connecting ridge to the rear, capturing one castle at a time and then using it as a base for the next attack. The strategy would have succeeded had Hideyoshi not mounted a surprise rescue operation by night, catching Shibata’s general unprepared.
Several sieges were involved in Hideyoshi’s invasion of Kyushu in 1586; the weapons used ranging from infantry assault to bribery and trickery. The Hojo’s mighty Odawara castle saw the most theatrical siege in Japanese history in 1590, where the besiegers loudly proclaimed their wealth of wine, women and song to the miserable Hojo defenders cooped up inside.
With the Korean invasion of 1592 the Japanese came up against foreign castle styles and siege techniques for the first time in their history. At first everything went their way. Thousands of arquebuses swept the walls of the Korean fortresses and an assault followed, a pattern that cleared a path as far as Seoul within 20 days. But when the Koreans rallied and the Chinese crossed the border to assist them the Japanese army was thrown on to the defensive, and had to withstand attacks from within the chain of communications forts they had hastily erected. At Chinju in 1593, however, the Japanese showed that they were able to conduct siege warfare with the same skill as the Chinese when they undermined the fortified town’s walls.
By the time of the second invasion in 1597 the only really secure Japanese possessions in Korea were the ring of coastal fortresses called wajô, which became the focus for sustained Chinese attacks. Ulsan was only half finished when it was subjected to human wave assaults in a celebrated winter siege where soldiers from both sides froze to death at their posts. Sunch’on was attacked by sea and land at the same time, the latter operation making use of weird and wonderful Chinese siege engines.
That ornate tower keeps already existed during the time of the civil wars of the 16th century is supported by the presence of such buildings on contemporary illustrations. This image is of Shizugatake castle, and appears on the Shizugatake Screen in Osaka castle. The actual buildings of this remote frontier fort would, however, have been less elaborate, and designs like this would have been found only in a daimyô’s more important castles.
The lessons learned in Korea were applied back home in the design of several of the fortresses we see today, but on returning to Japan the samurai split into two camps for the succession dispute that culminated in the battle of Sekigahara in 1600. Several key sieges, including Ueda, Otsu and Fushimi, provided ‘sideshows’ for this decisive battle. Finally, at Osaka in 1614/15, European techniques of long-distance artillery bombardment made their first appearance.