Advanced Guide to Reading the Nakago: Unlocking Sword History Through File Marks, Peg Holes, and Signatures

The Nakago (Stem): The Sword's "Official Document"

The nakago of a Japanese sword is the part of the blade that fits inside the handle (tsuka) and is typically not visible from the outside. The nakago contains the following concentrated information:

• Mei (signature): The swordsmith's name, year of manufacture, province name, etc.
• Yasurieme (file marks): The pattern of striations created by file marks (yasuri) on the nakago surface
• Mekugiana (peg hole): The hole for the mekugi peg that secures the handle
• Sabi (rust) color and texture: Evidence of aging

By comprehensively interpreting these elements, one can determine the sword's provenance, authenticity, and whether it has been modified. The nakago is an "indelible record," and the ability to read it accurately is at the heart of Japanese sword authentication.

Yasurieme (File Marks)—The Swordsmith's "Signature"

Yasurieme are the scratch patterns created by a file (a metal tool) applied to the surface of the nakago. Beyond mere finishing, they also serve the practical purpose of preventing the handle wrapping from slipping, but most importantly, they are crucial clues to the characteristics of the swordsmith and the region of origin.

Types of Yasurieme

Katte sagari (right-descending file marks): File marks that run downward to the right. The most common form, seen in many regions.

Suji gai (diagonal file marks): File marks that cross diagonally. Found in Bizen, Mino, and other regions.

Kiri (horizontal file marks): File marks running horizontally. Found in the koto period and in the Yamashiro tradition.

Higaki (cypress fence pattern): File marks forming a continuous V-shape pattern. A special form found in certain schools.

Kesho yasuri (decorative file marks): Decorative file marks applied for aesthetic purposes. Found in areas such as the maruage mei (shortened blade signature) of tachi.

Yasurieme Tendencies by Region and Period

However, since yasurieme may have been modified in later periods, judgment based on them alone is dangerous.

Mekugiana (Peg Hole)—Evidence of Usage History

The mekugiana is the hole for the mekugi peg that secures the blade to the handle, and the number of holes is an important clue indicating the sword's usage history and modification history.

One hole: The most standard. Swords from the early modern period onward typically have one hole.

Two or more holes: When there are two holes, it generally means one of the following:

1. The blade was mounted on two different handles (the handle was remade)
2. A shortening process (suriage) was performed, and when the nakago became shorter, a new hole was drilled
3. "O-suriage (major shortening)"—in cases where a tachi was converted into a katana

Position and age of holes: Old holes have deep rust, while new holes have shallow rust. When there are multiple holes, the age of each can be determined by comparing the degree of rust on each.

Reading the Mei (Signature)

The mei is the characters that the swordsmith carved into the nakago using a chisel (nomi) or engraving tool (tagane).

Types of Mei

Omote mei (front signature): The signature on the side that faces outward when the blade is worn at the waist (with the edge facing upward). Usually contains the swordsmith's name.

Ura mei (reverse signature): The signature on the inner side. Often contains the year of manufacture, the dedicatory temple or shrine, owner's name, and other information.

What Can Be Read from the Content of the Mei

• Swordsmith's name: The most direct evidence of "who made it." However, false signatures are common.
• Province name: May indicate the region of origin, such as "Yamashiro no Kuni" or "Bizen no Kuni"
• Official rank: Position names held by the swordsmith, such as "Mutsu no kami" or "Musashi no kami"
• Era name: The year of manufacture, such as "Horeki X year"
• Circumstances of blade forging: Historical information, such as "owned by a certain family" or "dedicated to a certain shrine"

Maruage Mei (Shortened Blade Signature) and Mumei (Unsigned)

When a tachi is shortened into a katana (maruage), the original signature may be removed. A blade that has lost its signature through maruage is called "mumei" (unsigned).

In some cases of maruage, the original signature area is folded back and forge-welded to the opposite side, preserving the signature (called "ori kaeshi mei" or "folded back signature," characterized by the signature being upside down). Additionally, "gaku mei" or "tanzaku mei" (framed or slip signature)—where the signature is cut into a strip shape and fitted in—is a different technique.

Nakago Shape—Characteristics of Period and Region

The overall shape of the nakago (length, form, shape of the point) is also an important element in authentication.

Bo-hi nakago (rod-shaped): A slender, elongated nakago. Common in tachi from the Kamakura to Muromachi periods.

Funazoko (boat-bottom) nakago: The point has a rounded, boat-bottom shape. Found in specific regions.

Kurijiri (chestnut-butt) nakago: The point has a rounded, chestnut-like shape. Common in the Yamato tradition.

Kiri (cut) nakago: The point is cut straight. The most common form.

Nakago Rust—Authentication through Aging

The rust on the nakago is evidence of aging and an important clue for determining the period of the sword.

Characteristics of old rust: Deep, dry appearance; a grayish-blue color called "ai-iro sabi" (indigo rust). Particularly seen on koto-period blades' nakago.

New rust (red rust): Reddish rust is relatively recent rust. However, depending on storage conditions, old blades may also develop red rust.

Artificial rust treatment: There is also a counterfeiting technique called "sabi ire" (artificial rust application) that creates rust artificially on the nakago. Distinguishing it from natural rust is often difficult, and expert authentication is necessary.

Conclusion—The Nakago Does Not Lie (As a Rule)

The yasurieme, mekugiana, mei, shape, and rust of the nakago are traces of hundreds of years of time. While the condition of the blade itself may change through later repairs and polishing, the nakago is not originally meant to be altered—this is why the nakago's evidential capacity is so high. Of course, skillful counterfeits do exist, but by comprehensively examining multiple observation points, one can approach the truth about the blade. The habit of carefully observing the nakago steadily cultivates and refines one's eye for Japanese sword authentication.