Nakago-jiri Shape Classification: Telling Kuri-jiri, Ken-gata, Ichimonji, Iriyama-gata, and Furisode-gata Apart

When appreciating Japanese swords, while attention tends to focus on the blade and appearance, the "nakago" (tang) that fits within the grip also contains much important information. In particular, the shape of the "nakagojiri" (tang end), which is the terminal portion of the nakago, has systematically organized types and represents essential foundational knowledge for understanding a sword's characteristics.

About Nakagojiri

The nakago is the part of the blade that fits within the grip, where the maker's signature, yasuri-me (file marks), and mekugi (peg holes) are inscribed. The tip of this is called the nakagojiri. The nakagojiri is the final part finished by the sword smith, and its form easily reveals the characteristics of schools, periods, and individual smith's habits. The form of the nakagojiri also serves as a clue for determining whether or not the sword has undergone suriage (shortening), and thus it is noted in both appreciation and authentication.

Below, the representative forms of nakagojiri are organized.

Main Types of Nakagojiri

• Kurijiri is a rounded form like the bottom of a chestnut, the most commonly seen nakagojiri. It is used on many swords and can be said to be the standard form.
• Haagari kurijiri is a variation of kurijiri with the outline on the blade side raised higher, having a somewhat asymmetrical rounded form. It is seen widely alongside kurijiri, and there are also many works that represent an intermediate form between the two.
• Kengyou is a form where the left and right taper symmetrically into a pointed, mountain-like shape, appearing like the tip of a sword. It gives a crisp, taut impression.
• Ichimoniji is a form where the nakagojiri is cut straight horizontally. It is severed in a horizontal line like the character "一" (one).
• Iriyamagata is an asymmetrical pointed form where the tip tapers and the point is offset toward the mune (spine) side. The outline on the blade side is longer and the mune side is shorter, so the heights differ left and right. Those that taper symmetrically left and right are distinguished and called kengyou.

Note that "furisode-gata" is not a form of nakagojiri itself, but rather a category referring to how the entire nakago curves in a large arc like a furisode (wide-sleeved kimono), and it belongs to a different perspective from the above nakagojiri form classification.

What Can Be Read from Form

The form of nakagojiri reflects the characteristic habits of the sword smith and school, and thus becomes one clue in considering the lineage of the work. For example, furisode-gata tends to be seen on older short blades, and certain connections between form and period/sword type have been noted. However, one cannot determine the maker or period based on nakagojiri alone; the principle is to judge by considering it together with other elements such as the maker's signature, yasuri-me, jigane, and hamon.

Also, when a originally longer tachi undergoes "suriage" (shortening), the nakagojiri is sometimes remade. The presence or absence of suriage can also be inferred from the relationship between the form of the nakagojiri and the position of the maker's signature.

The Relationship Between Suriage and Nakagojiri

Suriage means to remake a long blade into an easier-to-handle length by shortening it from the nakago side. Since the nakagojiri side is cut short and a new nakagojiri is made, the original form of the nakagojiri is lost. If it is cut deeper than the position of the maker's signature, the signature is also lost, resulting in the state known as osuriage musei (large suriage, unsigned).

Nakago that has undergone suriage often retains traces such as yasuri-me changing partway through or multiple mekugi holes. By observing both the fashioning of the nakagojiri and these traces together, one can infer the history the sword has followed. Suriage has been widely practiced according to the practical needs of the times, and one need not simply consider that a sword with suriage has lower value.

Reading Together with Yasuri-me

An important viewing point of the nakago alongside nakagojiri is yasuri-me. Yasuri-me are file marks made to prevent the nakago from slipping within the grip. There are many types, such as straight horizontal "kiri," and diagonally applied "katte-sagari" and "suji-kai," and the conventions differ by school and smith. When the form of nakagojiri and the type of yasuri-me are observed together, the clues for considering lineage increase further.

Also, the color of rust on the nakago is important information. The principle is to leave the nakago unpolished and let it age naturally, and the rust color that deepens over long years becomes material for estimating the period. That is why removing or polishing the rust on the nakago is strictly forbidden. Polishing the nakago with good intentions ends up erasing the very information that tells of its age.

Recommendations for Observation

To observe nakagojiri, first grasp broadly whether the overall outline is rounded, pointed, or flat. Then, by observing whether it is symmetrical or asymmetrical and whether it has a curve, one can more easily determine its type. Although the nakago is hidden within the grip, it is an indispensable information source for understanding the sword's characteristics.

Some information concerning the nakago is also recorded in the firearms and swords registration certificate. Since the certificate records blade length, curvature, the number of mekugi holes, and so on, making a habit of comparing the certificate's entries with one's own sword becomes a natural opportunity to observe the nakago carefully. It is customary to count mekugi holes including those that have been filled in.

When observing the nakago in online images, it is good to check in order: the outline of the nakagojiri, the number of mekugi holes, the direction of yasuri-me, and the position of the maker's signature. Since the symmetry or asymmetry of the outline can be difficult to discern depending on the angle of the photograph, it is even better to have photos of both front and back sides.

Our website displays handled blades in an online catalog, which may include images of the nakago. These can be used as material for comparing nakagojiri forms in images. If you have any concerns, please confirm details via the contact form before purchase.