Nakago and Yasurime: Japanese Sword Tang Filing Marks Explained

When examining a Japanese sword, most people naturally focus on the blade, hamon, or fittings. However, one of the most important areas for understanding a sword's history and construction is often hidden inside the handle.

This area is called the Nakago, or tang. The Nakago may contain valuable information about a Japanese sword, including the swordsmith's signature, the date of manufacture, and other historical inscriptions. It can also display distinctive filing marks known as Yasurime.

These seemingly simple lines on a Japanese sword tang can provide useful clues about the swordsmith, school, period, and traditional construction of a katana.

What Is the Nakago?

The Nakago is the portion of a Japanese sword blade that extends into the handle, or tsuka. In English, this part is commonly called the tang.

Unlike many modern decorative swords, a traditionally constructed Japanese sword has a tang that is an integral part of the blade. The Nakago extends beneath the handle and helps secure the blade to the tsuka.

The Nakago is usually not polished in the same way as the visible blade. Instead, its surface often retains a darker, aged appearance and may contain important information about the sword.

Depending on the sword, the Nakago may include:

• The signature of the swordsmith, known as a Mei
• The date the sword was made
• The location or province associated with the swordsmith
• The name of a school or tradition
• Cutting test inscriptions
• Ownership or historical markings
• Distinctive filing marks known as Yasurime

For collectors and students of Japanese swords, the Nakago can be one of the most informative parts of a katana.

What Are Yasurime?

Yasurime are filing marks found on the surface of a Japanese sword tang. The word refers to the lines or patterns created when the swordsmith uses a file on the Nakago.

These marks usually appear as a series of straight or angled lines running across the tang. Although they may look decorative, Yasurime traditionally served practical purposes during the construction of a Japanese sword.

The pattern of Yasurime can vary depending on the swordsmith, the historical period, and the school of swordmaking.

Because of these differences, experienced collectors and Japanese sword researchers may examine the filing marks as one of several characteristics used when studying a blade.

Why Does a Japanese Sword Have Filing Marks on the Tang?

Yasurime were not originally created simply for decoration. The filing marks on the Nakago have practical functions related to the construction and assembly of the sword.

One important purpose is to create a textured surface on the tang. This texture can help the wooden handle fit securely around the Nakago.

A completely smooth tang may provide less grip between the blade and the wooden core of the tsuka. Filing marks create a rougher surface and are part of the traditional finishing process.

Over time, however, the appearance and pattern of Yasurime also became associated with particular swordsmiths and swordmaking traditions.

The Different Types of Yasurime Patterns

Japanese sword filing marks can appear in several different patterns. The direction and arrangement of the lines may vary significantly.

Some commonly recognized Yasurime patterns include:

• Kiri – horizontal filing marks
• Sujikai – diagonal filing marks
• Katte-sagari – diagonal marks descending in a particular direction
• Katte-agari – diagonal marks ascending in a particular direction
• Kesho Yasurime – decorative filing patterns

The exact appearance of a Yasurime pattern can vary. In many cases, the marks are not perfectly uniform because they were created by hand during the finishing of the Nakago.

This is one reason why examining the tang of a Japanese sword can provide insight into traditional swordmaking techniques.

Yasurime and Japanese Swordsmith Identification

One of the most interesting aspects of Yasurime is their potential value in the study of Japanese swords.

Different swordsmiths and swordmaking schools developed their own working methods. The shape of the Nakago, the style of inscriptions, and the pattern of the filing marks could all contribute to the overall characteristics of a sword.

In some cases, Yasurime may help researchers compare a sword with known examples from a particular school or historical period.

However, filing marks alone are generally not enough to identify a swordsmith with certainty. Japanese sword identification usually involves examining multiple characteristics, including:

• Blade shape
• Sugata
• Hamon
• Jihada
• Nakago shape
• Mei or signature
• Yasurime patterns

For this reason, Yasurime should be viewed as one piece of information within a broader examination of a Japanese sword.

Decorative Yasurime on Japanese Swords

During the development of Japanese swordmaking, filing marks gradually became more than a purely functional feature.

By the Edo period, some swordsmiths paid particular attention to the appearance of the Nakago. Decorative filing patterns, often called Kesho Yasurime, became more common on certain swords.

These filing marks could be arranged carefully to create an attractive and distinctive appearance.

The use of decorative Yasurime demonstrates the level of craftsmanship involved in traditional Japanese swordmaking. Even parts of the sword that were normally hidden inside the handle could receive careful attention from the swordsmith.

Why the Nakago Is Important When Studying a Katana

The Nakago is often described as one of the most important historical areas of a Japanese sword.

While the blade may be polished or restored over the course of its life, the tang can preserve information that provides clues about the sword's origin and history.

The patina that develops naturally on an older Nakago may also be significant. For this reason, collectors generally avoid aggressively cleaning or polishing the tang of an antique Japanese sword.

Removing the natural surface of an old Nakago may damage historical information and make it more difficult to study the sword properly.

The combination of the Nakago's shape, inscriptions, patina, and Yasurime makes it an important area for anyone interested in traditional Japanese swords.

Nakago Patina and the Age of a Japanese Sword

Over time, the surface of a Japanese sword tang naturally develops oxidation and patina. This appearance is different from the polished surface of the blade.

A traditional Nakago is normally allowed to age naturally. Its surface may gradually become darker as the sword becomes older.

For antique Japanese swords, this natural patina can be historically important. Excessive cleaning, sanding, or polishing may permanently alter the tang.

For this reason, the Nakago should generally be treated differently from the visible blade. Antique swords should be handled and maintained carefully, especially when the tang contains a signature or other historical inscriptions.

Nakago vs. Full Tang: What Is the Difference?

The Japanese term Nakago and the English term tang refer to the portion of a blade that extends into the handle.

However, the term full tang is commonly used in modern sword and knife manufacturing to describe a blade construction in which the tang extends through the handle.

A traditional Japanese sword uses a Nakago that extends into the tsuka and is secured using a mekugi, or bamboo peg.

Although modern terminology may describe many Japanese swords as having a full tang, traditional Japanese sword construction follows its own specific methods and terminology.

Understanding the Nakago helps buyers better appreciate how a traditional katana is assembled.

Should You Clean Yasurime on a Japanese Sword Tang?

In general, the tang of an antique Japanese sword should not be aggressively cleaned.

The natural patina, filing marks, and inscriptions on the Nakago may provide important historical information.

Using sandpaper, polishing compounds, abrasive tools, or aggressive cleaning methods can permanently alter the surface of the tang.

If you own an antique Japanese sword and are unsure how to care for the Nakago, it is best to consult a qualified Japanese sword specialist before attempting any restoration.

How to Examine the Nakago of a Katana

The Nakago is normally hidden inside the tsuka, so it should not be removed casually.

Traditional Japanese swords are constructed with a mekugi that helps secure the handle to the tang. Removing the handle incorrectly can damage the sword, fittings, or wooden tsuka.

If examination is necessary, the sword should be handled carefully and with appropriate knowledge of Japanese sword construction.

Important features to observe include:

• The overall shape of the Nakago
• The direction of the Yasurime
• Any inscriptions or signatures
• The number and placement of mekugi-ana
• The condition of the tang surface
• The natural patina of the Nakago

These characteristics can help provide a better understanding of the sword's construction and history.

The Nakago and Yasurime in Traditional Japanese Swordmaking

The Nakago is much more than the hidden end of a katana blade. It is an important structural and historical part of a Japanese sword.

The filing marks known as Yasurime demonstrate the practical techniques used by Japanese swordsmiths during the finishing process. At the same time, the different patterns can reflect traditional schools, individual working styles, and historical developments in Japanese swordmaking.

For collectors, enthusiasts, and anyone interested in the history of the katana, learning about the Nakago provides a deeper understanding of how Japanese swords were made.

The next time you study a Japanese sword, remember that some of the most interesting details may be hidden beneath the handle.

Frequently Asked Questions About Nakago and Yasurime

What is the Nakago on a Japanese sword?

The Nakago is the tang of a Japanese sword. It is the part of the blade that extends inside the handle, or tsuka, and helps secure the sword's blade to the handle.

What are Yasurime?

Yasurime are filing marks found on the surface of a Japanese sword tang. They are created during the finishing process and may vary in direction and pattern depending on the swordsmith or swordmaking tradition.

Why does a katana tang have filing marks?

Filing marks create texture on the Nakago and are part of traditional Japanese sword construction. Different filing patterns may also provide useful information when studying a sword's school, style, or period.

Can Yasurime identify a Japanese swordsmith?

Yasurime can provide useful clues, but filing marks alone usually cannot identify a swordsmith with certainty. Experts examine multiple characteristics, including the blade shape, hamon, signature, Nakago shape, and other features.

Should I clean the Nakago of an antique katana?

Generally, an antique Nakago should not be aggressively cleaned. Its natural patina, inscriptions, and filing marks may contain important historical information. If you are unsure, consult a qualified Japanese sword specialist.

What is the difference between a Nakago and a full tang?

Nakago is the traditional Japanese term for the tang of a sword. Full tang is a modern manufacturing term commonly used to describe a blade that extends through the handle. Traditional Japanese swords use a Nakago designed specifically for Japanese sword construction.

Where are Yasurime located on a katana?

Yasurime are located on the Nakago, which is the portion of the blade hidden inside the tsuka. They are normally not visible unless the handle is properly removed.

Final Thoughts

The Nakago and its Yasurime filing marks are important features of traditional Japanese swords. Although hidden inside the handle, the tang can contain valuable information about a katana's construction, history, and craftsmanship.

From the swordsmith's signature to the direction of the filing marks, the Nakago offers a fascinating look at the traditional methods behind Japanese swordmaking.

Whether you are studying antique Japanese swords or learning more about modern handcrafted katana, understanding the Nakago and Yasurime will help you appreciate the details behind the blade.