Japanese Castle Explorer

by Daniel O'Grady

       
Strongholds of the Samurai: Japanese Castles 250-1877 Imjin War book cover

Japanese Castle Walls

There existed a great variety of methods in stacking stones to construct stone walls & foundations. Small & large stones or blocks were used, some walls had rising curves while others rose evenly, some walls present a smooth face while others look roughy stacked. No matter the design or construction, there is no doubting the technical ability of their builders as these walls have stood for centuries.

Nozurazumi - 野面積み

The stones used in this technique had very little or no work done to them. The stones were rough & almost appear to look randomly stacked. These natural-faced walls were unsuitable for steep-angled walls.

Uchikomihagi - 打込み接ぎ

This is the most common method for making stone walls. The irregular edges are chipped away. Not a great deal of care is taken & the resulting wall could have an uneven surface with many small gaps that could act as hand & footholds.

Kirikomihagi - 切込み接ぎ

Great care is taken to shape & trim each block. The result being a wall with smooth surfaces with the smallest of gaps. Due to the amount of work required to make a wall with this technique, they were only made in times of peace.

Kikkōzumi - 亀甲積

The six-sided stone blocks resemble the pattern of a tortoise's shell, which is what gives them their name. They are also known as Hachi-no-su or honeycomb. The blocks are precisely cut to minimize any gaps.

Wood & clay walls

Sitting atop the stone walls are the wooden-framed & white-plastered walls known in Japanese as Shirakabe. A variation of the castle wall existed that was built up from clay & rocks then covered with the white plaster. In almost all cases stone, wood, or a combination of both were used as supports for increased strength. Commonly, there were openings in the walls that allowed defenders to see & indeed use their bow, guns & cannons on attackers should they venture within range.

Teppō zama - 鉄砲狭間

These three geometrically-shaped eyelets are commonly found in Japanese castles. They gave defending soldiers protection when observing or firing upon attackers. Some have covers which made them harder to detect from outside.

Ya zama - 矢狭間

This vertical, retangular shape was more suitable for archers.

Ishi zama - 石狭間

Ishi zama were located at the base of the wall & used by those with mini-cannons.

Namako kabe - 海鼠壁

Sea cucumber walls were first built in the early Edo period (1603 - 1868), and were predominantly found in western Japan. The early styles were of square tiles arranged horizontally. As time progressed, and as the Namako kabe spread to other areas of Japan, more and more variations in design and technique were developed. Read more