Japanese Castles

 

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Photo from www.greatbuildings.com

 

Background Information

 

The Development of the Japanese Castle

 

The earliest castles were actually manor houses that developed fortifications such as wooden palisades along the moats, wooden towers, and gates. It was in the Nara period (646-794) when the castles began to evolve into those seen today. Dazaifu built a mizuki (which means water fort) in Hakata Bay to protect against invasions from the Korean peninsula. More castle-like forts were built in northern Japan by the frontier guards against the aboriginal people of the regions.
The words kinowa and kinowasaku which contain the character ki "castle" mean a fort surrounded by walls and turrets. The character, ki became to be pronounced as shiro, and it is therorized this change happened in the Heian period (794-1185).

Picture from Feudal Architecture of Japan by Kiyoshi Hirai
Picture shows a drawing of Tokugawa Ieyasu's Osaka Castle

 

After the Onin Civil War (1467-77), local warriors started to become stronger and many fortresses were built. But as guns were introduced, these fortresses became more sophisticated and larger. They were usually built on steep mountain tops. They were then surrounded by stone walls and in the late middle ages, donjons (towers) were added. In building the castles, they used both man made and natural elements to defend them. These mountain castles are called yamajiro and the mountain top locations made direct attacks difficult. The only attack that could occur on the mountain castle were sieges. Because of this, additional buildings were needed in the castles to store food and weapons, in case of a long siege. Also because of the locations, the troops were stationed at the foot of mountains along with the daily living residences of the damiyos. Because of this a jokamachi (castle towns) would form. These first mountain castles were located in much more difficult to reach areas, for both the enemies and the people of the castles. Therefore later castles were built on hilltops. The hilltop castles were called hirayamajiro.
After the Age of the Warring Provinces (1482-1558), the damiyos that survived built larger castles as their lands and spheres of influence increased. Castles became more dignified and were political centers instead of military bases. They became symbols of power. Newer castles were built in open areas of political and economic concentration. These flatland castles were known as hirajiro. (ie: Nagoya and Nijo castles in Kyoto)

 

The Difference Between Japanese and European Castles

 

Although castles in Europe were built away from cities. Most were built in the cities and had surrounding walls to protect the people. Japan was rarely invaded by other countries and most of its warfare involved only its warriors and not its civilians. Therefore the castle towns were not regarded as part of the fortress.

Picture from Feudal Architecture of Japan by Kiyoshi Hirai Photo shows a castle town.

 

Architectural Breakdown

 

Building a Castle

 

Throughout what is known as the medieval period, builders relied on the landscape, such as mountains and rivers as part of the castle construction. The castles built under these circumstances are called yamajiro, which means mountain castles. Their walls were made of both rock and earth. Moats for these castles were not normally dug. They used the natural terrain as much as possible, which meant builders used existing rivers, or streams as moats for their castles.
Stone walls were very important in the construction of castles in Japan. However, they did not use mortar when building the walls. Instead, they used a dry masonary technique that locked the rocks into place. The term used to describe this technique is ranseki-zumi which means disordered stone piling.

Photo from Japanese Castles by Motoo Hinago.
Photo shows example of ranseki-zumi.

 

When the Japanese began to advance their castle building skills, their techniques became more sophisticated. They began to use large rocks that were shaped to resemble the Japanese burdock (this technique is called burdock piling) . They would build up these rocks against a hillside or mound of earth that had been previously prepared, and stuck the rocks into place using stone fill. They did the stone fill with kuri ishi which means chestnut stones, named for their small size.

Photo from Japanese Castles by Motoo Hinago.
This photo shows an example of burdock piling.

 

Eventually, castles were built on plains. Those particular castles are known as hirajiro which means flatland castles. Sometimes, builders used small hills on the plains when building their castles. Those castles are known as hirayamajiro or flatland-hill castles.

Photo from www.jcastle.info

When castle walls got too high, it was necessary to modify the slope of the wall to make sure they were stable. When this happened, the walls were curved. Curved walls are known as ogi no kobai or folding fan slopes.
The corner stones of most castles built in Japan were at right angles for proper alignment of the walls. However, there were a few castles whose corner stones are more than ninety degrees.
Sometimes the tops of the stone walls were not level, and curved upwards or outwards. It is thought that these techniques were not used for structural reasons, but more for aesthetic preference.

 

Important People in the Building Process

 

Bugyo or commissioners of work were appointed to supervise certain aspects of the construction of the castles. One of their jobs was to coordinate the efforts of the builders, craftsmen and laborers. During the Edo period, the work done by the bugyo was divided between the fushin bugyo and the sakuji bugyo. The fushin bugyo supervised the engineering aspects of construction, especially the construction of the stone walls. They were also in charge of organizing the supply of stones needed to construct the walls. The sakuji bugyo were in charge of architectural work, especially the wall towers and the tenshu.

Photo from Japanese Castles by Motoo Hinago.
This drawing shows the construction process of a Japanese castle.

 

Three Rings of Defense

 

A basic principle for castles built after the 1600s was the three rings of defense:

There were also three different types of the three rings of defense:

Protecting the Castle

 

Castles are different than any other type of building because most times they have a military purpose. Because they serve that purpose, they are attacked. When constructing castles in Japan, architecs used different techniques to help prevent damage caused by both military attacks and bad weather.
Fire is another element that the castles had to be protected from. Builders found a way to prevent fire from damaging the castles by using a fire resistent plaster. The method of completely covering a building with plaster is known as dozo-zukuri which means stuccoed storehouse construction. Not a single surface that was made out of timber was left umcovered. Even window shutters were coated with clay to prevent them from burning. When the castles had wood paneling, the boards were sometimes painted with lacquer to keep fire from doing a lot of damage.

Photos from Japanese Castles by Motoo Hinago.
Photo on left shows castle being prepared for plaster. Photo on right shows castle protected with stucco.

In addition, damage from musket balls on the outer walls of the tenshu and other important buildings was a worry for the Japanese. To prevent this damage they made the walls thicker by using two coats of under lathing and also filled the interstices with small stones, which added strength.
The Japanese were also worried about people breaking in to the castles through the windows, and came up with ways to prevent the break-ins from happening. They covered the wooden shafts of the window grills in sheets of iron. Covering the shafts with the iron made it hard to saw through. They then covered the sheets of iron with plaster to hide what they had done.
One natural element that often caused damage to castles was water. The castles sometimes had problems with drainage, and to fix that problem, they used open gutters. At critical places in the castles, large scale conduits made of stone were used to funnel the water into moats. When the wind would drive rain against the windows, even when shutters were closed, they would leak. Because of this, a hole was drilled into the window sill, which lead to a hollow metal pipe that drained the rain back out of the castle.

Photo from Japanese Castles by Motoo Hinago.
Photo shows pipes coming out of the wall, used as a drainage system when rain came through castle windows.

 

The Tenshu

 

The tenshu is the principal tower, and has a powerful symoblic role. Some of the first tenshus were observation towers that were on top of residential buildings, or even just on the roof of larger towers. The style of tenshus range from plain and unadorned to ebaborate. Some tenshus are single structures, whie others are a combination of both large and tall towers. As the castle became less of a military need and had more of a political and declaratory role, the tenshu became more symbolic. Decorations of two types were added to the tenshus, a chidori hafu or plover gable that is a triangular gable, and the kara hafu which means exotic gable which is an elegantly cusped gable. Originally the tenshu was a focal point of the castle, but when it became more symbolic it became separated from daily activity.

Photo from Japanese Castles by Motoo Hinago.
This is an example of a tenshu from the Hikone-jo castle.

 

Materials Used to Build a Castle

 

 

Buildings within the Castle

 

 

 

Castles in Okinawa

 

Okinawa is the site of many castle ruins. Over one hundred castle sites have been discovered there. Many of the castles in Okinawa were military fortifications; however, a few of the castles like Shuri-jo, Naka-gusuku, and Nakijin-jo were centers of both government and the community. The castles in Okinawa are different than those found on the mainland of Japan. Japanese castles were built with moats and stone walls. They have towers and parapets on top of the walls, and they had a tenshu. Okinawan castles did have stone walls, but they did not have moats, towers or parapets on top of the walls. The stone walls were the main structure of the the castles, instead of just being a foundation for timber frames like in Japan. Their walls curved instead of having corners with sharp angels. Most castles in Okinawa were abandoned or demolished as a result of the Satsuma annexation. Some of the castles are being restored, however.

Photo courtesy of www.jcastle.info
This is a photo of the Zakimi-gusuku castle in Okinawa