Blade, Measurements & Mountings
Sword Anatomy
A structured reference to the components, measurements, and mounting parts of the Japanese sword. Each term links to the glossary for fuller definitions.
Blade Components
The blade of a Nihontō is a precision instrument, with every part serving structural, functional, and aesthetic purposes. Understanding these components is essential for description, attribution, and appreciation.
Kissaki
The point section of the blade, defined by the yokote line. Contains the bōshi (tempered point pattern).
Yokote
The line separating the kissaki from the body of the blade. A defining feature of the Japanese sword point.
Monouchi
The cutting section of the blade, approximately the first few inches below the yokote. The primary striking area.
Ha
The edge of the blade. The hardened, sharpened cutting surface.
Mune
The spine or back of the blade. The thicker, softer edge opposite the ha.
Shinogi
The ridge line running along the length of the blade, separating the ji from the mune. A key structural and aesthetic feature.
Ji
The surface between the shinogi and the hamon. Displays the hada (grain pattern).
Hira-ji
The flat surface of the blade between the mune and the ha, including the ji.
Hamon
The tempering pattern visible along the edge, created by differential heat treatment.
Bōshi
The tempered pattern on the kissaki (point area). Its shape is a critical diagnostic feature.
Nakago
The tang of the blade, which fits into the handle. Contains the mei, yasurime, and mekugi-ana.
Mekugi-ana
The hole in the nakago through which the mekugi (retaining pin) passes to secure the blade.
Yasurime
File marks on the nakago. Their pattern helps identify the smith, school, or period.
Measurements
Sword measurements are recorded with precision and form the basis of formal documentation. These figures are essential for comparison, attribution, and record-keeping.
Nagasa
The cutting-edge length, measured in a straight line from the munemachi to the kissaki. The primary length measurement.
Sori
The depth of the blade's curvature, measured as the maximum distance between the spine and a straight line from munemachi to kissaki.
Motohaba
The width of the blade at its base, measured at the machi (notch near the habaki).
Sakihaba
The width of the blade at the yokote, near the point.
Kasane
The thickness of the blade at the mune, measured at the motohaba point.
Measurements are traditionally given in shaku (寸), sun (寸), and bu (分). One shaku ≈ 30.3 cm. Modern documentation often provides both traditional and metric measurements.
Mounting Parts
The mounting (koshirae) is a complete system of interrelated parts, each crafted by specialists. The mounting both protects the blade and presents it as a work of art.
Tsuka
The handle, constructed around a wooden core wrapped in samegawa (ray skin) and tsuka-ito (braid).
Saya
The scabbard, typically lacquered wood. Protects the blade and completes the mounting.
Tsuba
The handguard. A disc or plate that separates the blade from the handle and protects the hand.
Fuchi
The collar at the tsuka side of the tsuba, reinforcing the handle mouth.
Kashira
The pommel cap at the end of the tsuka, matching the fuchi in design.
Menuki
Decorative ornaments fitted beneath the tsuka-ito wrapping. Originally functional, now primarily artistic.
Seppa
Thin metal spacers on either side of the tsuba that ensure proper fit within the mounting.
Habaki
The wedge-shaped collar that secures the blade in the scabbard and locks the mounting assembly.
Koiguchi
The mouth of the scabbard. Should fit snugly against the habaki.
Kojiri
The cap at the end of the scabbard, protecting the wood and completing the mounting.
Sageo
The cord attached to the kurikata (knob) on the scabbard, used to secure it to the obi or hakama.
Mekugi
The retaining pin that passes through the tsuka and nakago, securing the blade.