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Seppa: Exploring the Design and Function of Washers

Written By: Abigail Cambal
Published On: February 14, 2024

Seppa are crucial yet often overlooked components of a Japanese sword, serving as washers or spacers fitted on either side of the sword guard. They can be found nestled between the ferrule and the sword guard, as well as between the blade collar and the guard. Seppa plays a vital role in the overall construction of Japanese swords, ensuring all parts of the sword fit tightly.

KEY TAKEAWAYS
Japanese swords typically use spacers or washers known as seppa to secure and tighten the blade to the hilt.
The seppa originally supported and strengthened the sword guard, which was made thin at the center.
The seppa-dai refers to the flat surface at the center of the sword guard, where the seppa is placed.

What Exactly Is a Seppa?

a seppa made of pure gold
Featuring a seppa made of pure gold – Credits: e-Museum

Seppa (切羽) are washers or spacers placed on both sides of the Japanese sword guard (tsuba) to ensure a tight fit. Originally, their purpose was to provide support and reinforcement to the sword guard which had a thin center.

oval outline of a seppa dai
Featuring the oval outline of a seppa-dai, where the seppa rested – Credits: e-Museum

The tsuba also features a “seat” for the seppa, called seppa-dai (切羽台), meaning base for the seppa.

Design and Function of a Seppa

Dismounted Japanese sword featuring a pair of oval seppa
A dismounted Japanese sword featuring a pair of oval seppa and other fittings – Credits: Mandarin Mansion Antiques
o seppa on a tachi
Featuring an ō-seppa on a tachi – Credits: Mandarin Mansion Antiques

A seppa’s oval shape follows the cross-section of a Japanese sword hilt and scabbard. It is made of thin, flat pieces of metal – commonly copper, brass, silver, or gold, and is often enhanced with gilded, gold-, or silver-plating. Depending on the size, it can be differentiated between small (ko-seppa) and large (ō-seppa) washers. Generally, a seppa’s size is about the same as the mouth of the scabbard and hilt.

Japanese sword with seppa on both sides of the sword guard
A Japanese sword with seppa on both sides of the sword guard – Credits: Mandarin Mansion Antiques

A seppa is used to fit and tighten the blade to the hilt, encircling the tang on either side of the sword guard. It is fitted between the ferrule or hilt collar (fuchi) and the upper part of the sword guard, as well as between the blade collar (habaki) and the lower part of the sword guard. Sometimes, more than one seppa is used on either side of the guard.

katana hilt with two seppa between the ferrule and sword guard
A katana hilt with two seppa between the ferrule or hilt collar (fuchi) and sword guard – Credits: Mandarin Mansion Antiques

Originally, seppa were designed to support the sword guard. Tachi swords from the Kamakura and Nanbokucho periods had to be light enough to be wielded with one hand. Therefore, their guards were often made from thin iron plates reinforced with two large seppa (ō-seppa). These ō-seppa were typically made of leather or copper, sometimes with gilt edging for extra strength.

seppa roughly the size of the scabbards mouth
A seppa roughly the size of the scabbard’s mouth when sheathed – Credits: Mandarin Mansion Antiques
seppa between the blade collar and sword guard
A seppa between the blade collar (habaki) and sword guard – Credits: Mandarin Mansion Antiques

The Seppa-Dai on the Sword Guard

Illustration of a Japanese sword guard showing the seppa dai
An illustration of a Japanese sword guard showing the seppa-dai, where the seppa is placed – Credits: Mandarin Mansion Antiques

The center of a Japanese sword guard has a flat area called the seppa-dai, encircling the opening for the sword tang (nakago ana). Since the seppa-dai is usually covered by the seppa, it is often plain and undecorated. Typically, the seppa-dai is thinner than the rest of the guard.

seppa dai on a tsuba signed by its maker
Featuring the seppa-dai on a tsuba, signed by its maker – Credits: Mandarin Mansion Antiques

The signature of the sword guard’s maker is often found on the seppa-dai, with their name on the left side while the right side may contain additional details such as residence, date of manufacture, and more.

tachi featuring an oval seppa
A tachi featuring an oval seppa resting on an oval seppa-dai – Credits: Mandarin Mansion Antiques

The seppa-dai’s oval outline usually matches the cross-section of a Japanese sword handle and scabbard. However, exceptions include nanban (Southern Barbarian) style sword guards that exhibit foreign influence, some presentation tsuba, imported guards from China, and Japanese copies of such guards.

nanban style sword guard with a rectangular seppa dai
A nanban-style sword guard from Japan with a rectangular seppa-dai – Credits: Mandarin Mansion Antiques
Some Japanese-made tsuba have rectangular seppa-dai. These were inspired by Chinese guards as angular hilts were common in China during the 17th and 18th centuries, despite being mounted on Japanese hilts with an oval cross-section. Other examples of sword guards also exhibit uncommon seppa-dai shapes.
Sources Cited
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