A brief on Japanese Fortifications

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A Brief on Japanese Fortifications:

Inspired by Hoel's thread in the Tutorial Forum, I've decided to post this brief on Japanese fortifications. I posted it here, as this will only be a few posts, certainly not the essays in Hoel's thread. I lack the artillery/fortifications training that he has - I am envious of that. I have been to Japan and visited both Himeiji Shiro (Osaka Castle) and Matsue Shiro - a smaller provincial castle held by the local prince or warlord (daimyo) in the western province of Shimaneken, Japan.

The primary difference in Japanese structures versus European structures, is that Japanese structures and castles (shiro) are made of wood, not stone. From a military standpoint, that seems almost silly - just burn the thing down right? In medieval Japan, arson was considered the most serious crime. Those convicted of arson were burned to death.

The reason for using wood instead of stone is due to the fact that the Japanese volcanic island chain frequently suffers earthquakes. If you build a fortification in stone and every 20 years or so there is a major quake. You spend all your time and money rebuilding from a pile of rubble.

Japanese castles, called "shiro" had several different phases in design - the discussion here are for the earlier castles, as later ones were built on flat ground and were more offices of state than defensive structures.

Earlier Japanese castles were built on mottes of rammed earth, man-built hills, similar to motte and bailey structures of early European style. The outside of this foundation/hill was encased in stone. The masons who built these foundations were careful to keep the secret on how they constructed them - often surrounding the entire motte with a fence, so passersby could not see the work being done, or how it was being done.

Unlike many round hill mottes of Europe, the Japanese motte was always square, like the final shape of the fortification to be built upon it.

The castle itself would begin as two heavy and long pieces of timber set at the center of the motte spaced apart so the opening between them would house the central stairway. The placed timbers were the height of the proposed structure. The rest of the castle was built around these two pieces of timber.

Another feature of the castle itself, as one can see from photos of them, are the stack of roof structures used in their construction. Looking at a shiro with a stack of five roof structures might indicate to a viewer that there were five levels to that particular shiro. Not so, this was a ruse, the roof structures are meant to confuse onlookers, often a 5 roofed shiro had 7 or more floors within. The roof structures are there to hide how many floors there actually were. Knowing the number of actual floors could indicate to an attacker how many defenders were within. Often extra floors were hidden behind the various roof structures.

GP

Images below: square motte, motte encased in stone, and Himeiji Castle...

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When viewing the photo above of Himeiji Castle, notice the structures sticking out of the first floor above the foundation motte. Don't know the Japanese name for these at the top of my head, but the literal translation for these structures are "rock drops." These essentially allowed the defenders to be out and over the attackers below so they could drop rocks on them, as if through murderholes, found in European gatehouses.

Though I'd like to post a plan of the out buildings and outlying structures, few actual complete castle grounds and surrounding walls remain in Japan. Himeiji, though an exception to that was built during the time - gunpowder was being used and much of the outlying structures were built with guns and cannons in mind. So much of what was included in older Japanese castles do not apply to Himeiji's construction.

However, The Shiro or main donjon is usually in the center of multiple courtyards each with their own set of walls surrounding them. Basically attackers were forced into a spiral movement through the maze of walls and courtyards to get to the center and attack the main fortress itself. This allowed greater and longer exposure to the missle weapons being fired from the fortress onto the attacking forces.

Also because the attackers were forced to travel round and round the castle to reach it, secondary donjons are castle structures were built on corners and areas adjacent to the main fortress. Though this allowed additional defenders to attack from the real purpose was subterfuge. Wearing armor, traveling in formations while being attacked from the donjon and spiralling around the castle. Attackers would get confused on which tower was the actual fortress.

One additional feature is that each courtyard and access path had its own gatehouse leading to the next courtyard further inside the complex. These gatehouse were built at 90 degree angles to the courtyard within. Attackers who successfully batter down through the gatehouse would find themselves being attacked in the flank by the defenders within. Making bypassing gatehouses even more dangerous.

Below is an example of this type of gatehouse construction. The red arrow represents the attacking force, the arrows represent the flank formation of defenders.

If I can find a complete castle grounds layout, I'll post it here as well.

That's about the extent of my understanding of Japanese fortifications.

One of the these days, I'd like to create a complete Japanese castle plan with outlying buildings and the wall and gatehouse complex for use in the many RPGs based on ancient Japan, like L5R.

GP

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One final point, Japanese castles did not have underground structures like dungeons, cellars or tunnels - except for one.

I mentioned having visited Matsue Castle in Shimaneken. This castle is unique in that it had a tunnel that connected the main fortress with one of the outlying lesser fortresses, primarily for missle assaults - the outlying tower defended a corner of the outer wall. I thought is was cool at the time, I got to visit the unique castle.

Regarding Himeiji castle, as it was built in 1592, defense from artillery was a big deal for that castle and the moat system included 3 different moats the furthest to prevent ranged guns to reach the main castle itself (at least in the technology available at the time of construction.)

These moats are deep, about 60 feet deep, were generally dry moats with stone walls encasing the the moat walls. Some of these moats were 100 feet across. The bridged lands that crossed the moats were located on different sides of the castle forcing attackers to have to move around the castle to reach the next bridge to cross the next moat.

GP

[Hoel]

The spiral design is a common feature in european medieval fortresses too. Gate houses would often postition the gates at an angel to prevent the use of rams inside. Forcing the enemy to constantly circle the defenses to get to the next gate is a central design idea.

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Because of my lack of knowledge on European castles, I did not realize this design feature was common to both Japanese and European castles. I only know Japanese castles to any level detail.

I'm sure you didn't know, Hoel, but I am half-Japanese. So therein is where my interest in Japanese fortifications are from. The last time I was in Japan was in 1977, the time before, I was just one year old child...

I didn't mean to one-up you on fortification discussion - its just your thread brought this idea back into my thoughts, so I thought I post my limited knowledge to your discussion. I didn't want to cloud up your discussion, so I didn't post this in your thread...

GP

[Hoel]

Oh, i don't mind. If I ever try to design a japanese castle I know where to turn.
I've never been interested in eastern history, our own is too much to keep track of without trying to learn a whole new culture.
Since we have a river police, I think we should have someone pointing out fortification flaws. If we can find someone who's expert on agriculture, we probably all could use a few pointers about fields and farmlands. Then there's harbours... Well.. All expertise that can make a map better is good in every way.
If i put together my essay as a pdf, do you think I can rip your text?

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Please do!

GP

[Asharad]

Oooh...Oooh! I've been to Japan. I was nearly tackled by guards at the Imperial Palace, because I was standing to close to the mote.

The area around Fujiyama is beautiful, if you ever get a chance. Also visit the lake around Hokone. Pure beauty.

PS - Try some Yakitori and Sukiyaki.

[Hoel]

I'm not the travelling kind, but I'll keep it in mind if i ever get teleported to the other side of the world

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Oooh...Oooh! I've been to Japan. I was nearly tackled by guards at the Imperial Palace, because I was standing to close to the mote.

The area around Fujiyama is beautiful, if you ever get a chance. Also visit the lake around Hokone. Pure beauty.


PS - Try some Yakitori and Sukiyaki.

I climbed Fujiyama - more a hike, really - took me 7 hours to get to the top and 10 minutes to get down, on foot. Did the whole Tokyo, Osaka, Hiroshima by bullet train, swam in both the Pacific and Sea of Japan side of the island, I've got family in Shimaneken, Yokosuka (near Kamakura), and Yokohama. I eat Japanese food all the time...

One of my cousins came here on a post college trip with college buddies (architects) seeing American architecture - they rented a car and drove from coast to coast to coast. We're all too busy to see each other now.

Oh, my old avatar was a 3D model of a kabuto (Samurai Helmet and war mask) which is part of my Boy's Day miniature Samurai War Armor and stand. May 5th (not just cinco de mayo) is Boy's Day in Japan, celebrated with Carp Kites, and a Shogun's suit of armor put on display...

I was on a shopping trip to Yokohama, with my Mom and sister, the Boy's Day accoutrement were on display. The wooden box, where one would put the display away, and used as a seat for the armor stand was alone. A little 3 year old Japanese boy, sat on it. The top is like veneer, very thin wood and it partially crushed under his weight. The price tag on the armor set was 100,000 yen, which in 1977 was $500 (made of steel, silk, horsehair - quality hand-made work) the shop manager looked at the broken lid, looked at me, then with a marker crossed off a "0" so it went from 100K yen to 10K yen, or $500 to $50 - so I bought it. Its still my favorite souveneer and I put it up on display for the whole month of May, each year...

GP

PS: sorry for the threadjack on my own thread!

PPS: this weekend, I'll dig it out, set it up and take photo to post here...