Katana anatomy - Things you need know to truly understand the sword of Samurai

There are many parts of a katana, and it can be confusing for those who are new to this piece of art. It's easy to get lost in all the terminology, for Japanese katana, basically there is a specific name for every detail. so we've put together a guide of the most commonly seen terminologies to help you understand what these words mean. With these knowledge, you will know better how to custom your own katana.

Blade
The blade is the main component of a Katana, and it is impossible to have a Katana without a blade, because the word “katana” literally means “one sided blade. In ancient Japan, traditional katana should be made of Tamahagane (玉鋼) , essentially it’s a type of high carbon steel. The making of tamahagane is very costly in terms of labour and time, it’s a luxury to use it nowadays. Most modern katana are made of modern steels like carbon steel, manganese steel, T10 steel etc.

Tsuka (柄)
The “Tsuka” (handle / hilt) refers to the gripping part of the sword, and the “tang” (nakago) is stored inside. The core of the handle is mostly made of wood, secured with mekugi pins, cover with samegawa, then wrapping with cords. A good tsuka should be tight and secure, no loose parts, and provide comfortable gripping to the user.

Saya (鞘)
Saya is the part used to protect the steel blade and is also known as the sword's scabbard. Most saya are made of wood, covers with lacquer and beatiful pattern, drawings. Generally speaking there are 2 types of Saya, the ones with many fitting , looking alluring, is for taking the katana out for use. The other type is shirasaya, basically the plain wooden saya without any decorative elements, used to store the blade for long time.

Kissaki 切先
Kissaki refers to the sharp point, the tip of a Katana, generally speaking it is the sharpest part of a katana. There are different types of Kissaki, classified by length there are Okissaki (大切先, longest one), Chukissaki (中切先, middle and most common one) and Kokissaki (小切先, shortest one). Traditionally Kissaki has different forging method and process, and in different era there are different types of Kissaki, it’s one of the factor to identify the sword age.

Boshi 帽子
The hamon line in the Kissaki part is called Boshi, in Japanese it’s called 帽子, literally means “Cap” or “Hat”. Bring out hamon line in this small area will require tremendous amount of time to polish. So it is one of the feature that reflects the craftsmanship of the swordsmith, or in this case, the togishi (研師), the craftsman who specialized in katana polishing. There are many types of Boshi as well, but noted that only clay tempered Katana has Boshi, because it’s part of the hamon.

Yokote 横手
Yokote is the dividing line between the sword's body and the kissaki. The Japanese name is 横手.Yokote was the result of forming the Kissaki during the forging process, technically speaking all Shinogi-zukuri (鎬造) katana should has Yokote. It takes polishing to make it look clear, and if you touch it with your hand you will feel the little hump.

Hasaki / Ha 刃先 /刃
“Ha” (刃) means “Edge” in Japanese, “Hasaki” (刃先) is another way of saying it. They refer to the cutting edge of the katana blade.

Mune 棟
Mune is the back of the katana, in Japanese it is called “棟”, means “Ridge”. As result of clay tempering, Mune is generally softer than the edge, to keep flexibility of the blade, so it’s not brittle when cutting against hard objects.

Shinogi 鎬 / Shinogi-Ji
"Shinogi" is the ridge line on the side of the blade (between the blade and the ridge). There are different types of katana shapes, the most common one is Shinogi-zukuri(鎬造), also known as hon-zukuri (本造) . This shape makes katana light, sturdy and sharp, it’s one of the reason why katana is such a great cutter.

Monouchi (物打）
The sharp edge below Yokote, about 3 inches, close to the middle part, is called Monouchi (物打). In actual battle Monouchi is most often used, especially for cutting and slashing moves, that’s why the name in Japanese means “Hit”.

Sori （反）
The curvature of a katana is called Sori (反). This is not an actual component of a katana, but it plays an important role in the development of katana. There are about 6 types of Sori, and they were all once popular in different period in the Japanese history.

Nagasa (長さ)
Nagasa (長さ) refers to the blade length of a katana, measuring from the end of the habaki to the Kissaki. Standard katana usually is about 28” long, which is about 72 cm. There are no set rules about the nagasa, if you want a custom katana with customized blade length, that is totally fine.

Bo-Hi (棒樋)
Bo-hi is the fuller on the blade. The kanji symbol for Bo-Hi is 棒樋 which combines the characters for “weapon" (棒) and “gutter" (樋). Bo-Hi is also known as blood groove, and many might think Bo-Hi is designed to create a channel so the blood can flow out, and the sword won’t stuck in the enemy’s body. But the truth is the purpose of having a Bo-hi, is to reduce the weight.

Hamon (刃文)
Possibly the most attractive, fascinating and aesthetic part of a katana, is the Hamon. In Japanese it’s called “刃文”. “刃” means blade, “文” means “Text / Pattern” . The hamon in Japanese swordsmithing is the visible effect created on the blade by the clay tempered process, it is the decisive factor in distinguishing the production time and place of production of Japanese nihonto.

Habaki (鎺)
Habaki (鎺) is the blade collar at the bottom of the blade, not only it holds the blade and scabbard together and tight, but also prevents the scabbard from coming into direct contact with the blade.

Munemachi (棟区)
Munemachi is a small notch that you can find on the back of the Katana spine. In Japanese Munemachi (棟区) roughly translated to “Ridge area”. The length of Nakago is measured from Munnumachi. The purpose of the Munemachi is to fit the blade collar tightly against the blade.

Tsuba (鍔)
Tsuba is the hand guard of a katana. the purpose of this component is to protect the hand of the person using the sword from getting cuts on it. It’s also highly valued as an independent art and craft. Tsuba is usually round or square, in iron or copper / brass material.

Seppa (切羽)
Seppa are 2 tiny metal plates that you can find on both sides of the Tsuba. The name “切羽” in Japanese means “Cut the feather” These are used as spacers to fill the gaps and secure the tsuba and the blade.

Fuchi (緣) & Kashira (頭)
Fuchi (緣) is the metal collar under Tsuba, Kashira (頭) is the metal cap at the bottom of the Tsuka. They are usually paired, in Japanese they are called “Fuchigashira” (緣頭). Their function is to secure and reinforce the Tsuka.

Menuki (目貫)
Menuki are a pair of metal piece under the Ito wrap, one on each side of the Tsuka, basically one for right hand and one for left hand. They are mainly for decoration, usually made of copper or brass, in the shape of different mythological creatures. They do provide better gripping, and helps with hand placement.

Nakago (柄)
The part of the blade inside the Tsuka is called “Nakago”, which is “tang”. For Nihonto, Nakago is usually made of low carbon steel, which is softer and can absorb certain level of shocking. In ancient Japan, swordsmith will engrave their name on the Nakago, as their “trademark”. This mark is called “Mei” “銘”. Different swordsmith schools has different styles of Nakago shapes.

Mekugi (目釘)
The pegs that connect handle and the blade, are called Mekugi (目釘). Traditionally they are made of bamboo, some will use brass as well. Mekugi are hammered inside the holes in the tsuka and nakago so they can connect firmly, to dissemble the tsuka you will need to use a tiny hammer to gently push them out as well

Tsuka-Ito (柄巻)
The wrapping on the Tsuka is called Tsuka-ito (柄巻). Common materials are cotton, silk, leather. Tsuka-ito keeps tsuka and the blade together, and provides better griping for the user, so it has to be tight and secure. There are many types of Tsuka—Ito.

Samegawa (鮫皮)
underneath the Ito is Samegawa, the name literally means “Shark skin” in Japanese, but actually ray fish skin is commonly used. It is used to cover the wooden plate of Tsuka, and provides better gripping because of the rough texture.

Koiguchi (鯉口)
The opening of the saya is called Koiguchi, the Japanese name literally means mouth of a carp, It was because its shape resembles it. It should be made perfectly fits the katana, and prevent the blade from constantly cutting against the saya. The outside of Koiguchi is usually cover with another “cap” to further protect the blade, usually in brass or horn material.

Kurigata (栗形)
The Knob cord retainer on the saya is called “Kurigata”, the name “栗形” in Japanese means “Shape of chestnut”. Inside the Kurigata is a small metal ring called “Shitodome”. Kurigata is used to tie the Sageo.

Sageo (下緒)
The cord that connects your katana with your obi (belt) is called Sageo. Sageo is tied on the Kurigata, Sageo is usually made of cotton, and about 180-220 cm long.

Kojiri (鐺)
The little metal cap at the bottom of the saya is called Kojiri. The purpose is to provide better protection to the saya because this is the Kissaki stored.