How to Choose an Authentic Japanese Sword

Many people purchase “swords,”

but very few actually own genuine Japanese swords.

Here are five key points to check before buying:

Genuine Japanese swords are crafted in Japan using centuries-old traditional techniques.

Appraising a Japanese sword involves determining “who made it, when, and where,” “whether it is genuine,” and “its value and historical significance.” It is not merely a visual inspection but a comprehensive assessment based on sword studies, history, and metalworking techniques.

Here, we explain step-by-step what is examined during an actual appraisal.

Key Points Examined in Appraisal

① Form (Sugata)

First, the overall silhouette.

*   Curvature depth
*   Blade width
*   Tip shape
These indicate the approximate era.

Example:

Kamakura period → Strong curvature, elegant
Edo period → Shallow curvature, practical
The form speaks to the “historical context of the sword.”

② Jigane (Forging Pattern)

The surface pattern of the steel.

Itame (Plain Grain)

Kobitame (Fine Plain Grain)

Masame (Straight Grain)

This area reveals the forger's technique, showing characteristics of the school and swordsmith.

High-quality jigane appears translucent and has a “moist” look.

③ Hamon (Temper Pattern)

Pattern formed by quenching.

Straight Hamon

Irregular Hamon

Clove-shaped Hamon

This is where the greatest individuality appears.

The rhythm and activity of the hamon (such as feet, leaves, gold lines, etc.) help infer the swordsmith's school.

④ Nakago (Tang)

The most crucial point.

Rust condition

Shape

File marks

Signature (me)

The nakago is generally not polished, preserving evidence of its era.

The signature is a reference point, but since forged signatures are common, a comprehensive judgment is necessary.

⑤ Hamon (temper line)

The hardening pattern at the tip.

Depth of the return

Shape

This area also reveals the swordsmith's idiosyncrasies.

The essence of appraisal

Appraisal is...

the process of narrowing down the period and school through the accumulation of characteristics.

Do not judge based on a single point alone.

Consider the overall form + jigane + hamon + nakago + boshi

as a comprehensive whole.

Experts also observe the overall aura (quality) of the piece.

Verify if it has a certificate issued by an accredited organization like the Japan Art Sword Preservation Society.

Without certification, its value is uncertain.

The Japan Art Sword Preservation Society (English name: Japan Art Sword Preservation Society, abbreviated as NBTHK) is a public interest incorporated foundation dedicated to preserving and promoting Japanese swords and related culture and techniques.

 It is Japan's leading sword organization, active in various fields including sword appraisal, archival management, and educational outreach.
Its primary activities include the appraisal and certification of swords.

The Society operates a Japanese sword appraisal system. Swords passing appraisal receive the following certificates and designations:

• Preserved Swords (Hozon Token)
• Specially Preserved Swords (Tokubetsu Hozon Token)
• Important and Specially Important Swords (works of high historical value and significance)

These designations also influence market value and historical positioning.

The beauty of the hamon (temper lines) and the texture of the steel reveal the sword's craftsmanship.

Hamon 

The hamon is the pattern that appears on the blade through quenching.
It reflects sharpness + beauty + the swordsmith's individuality.

Main Characteristics

Appears as bright white lines at the temper line

Varies in style by swordsmith and school

Appearance changes depending on preservation condition

Representative Types

Straight Hamon (Suguha) → Straight and composed impression

Wavy Hamon (Midare) → Wavy, vibrant pattern

Clove-like Hamon (Choji) → Rhythmic, flower-like pattern

Hamon is often called the “face of the sword.”

Jigane

Jigane = “Steel Skin”

Jigane is the steel grain pattern visible on the blade's body.
It directly reflects the results of the forging process.

Main Characteristics

When exposed to light, a grain pattern resembling wood grain becomes visible.

It reveals the forging technique and the quality of the iron.

It determines the blade's character.

Representative Grain Patterns

Itamehada → Grain pattern resembling wood grain

Koitamehada → Fine, tightly packed, smooth texture

Masamehada → Straight, linear grain pattern

Mokumehada→The surface of the jigane resembles tree rings.

Jigane is like the constitution” of the sword.

Has it undergone professional polishing?

Are there any cracks?

Does it retain its original handle?

Key Conditions to Check on Japanese Swords

① Rust

Most critical check.

Red rust → Active and dangerous

Black rust → Old, stable rust (normal on the nakago)

Red rust on the blade or ground significantly reduces value.

Never touch black rust on the nakago.

② Chips/Cracks

Damage to the cutting edge.

Small chips → May be fixable by sharpening

Deep cracks → Affects the blade's lifespan

Also evidence of practical use.

③ Bending/Twisting

A sword naturally has a straight curvature.

Unnatural bending → Possibility of impact or accident

Correction is possible but may not fully restore it.

④ Cracks/Splits (Fatal Damage)

This is the most dangerous.

Blade split

Ground split

Structural damage, basically irreparable.

A major negative in appraisal.

⑤ Condition of Sharpening

Excessive sharpening thins the blade.

Hiragana pattern fading

Thin meat placement

This is “over-sharpened”.

⑥ Integrity of Jigane and Hamon

Assess not just beauty but preservation condition.

Cloudiness

Fatigue (weakened jigane)

These are signs of long historical use.

⑦ Preservation of Nakago (Tang)

This is evidence of its age.

Natural rust

Condition of the inscription

Be cautious of shaving or machining.

Basic Judgment Criteria

Roughly speaking:

Is there any critical damage?
Has it been sharpened down excessively?
Is the overall preservation sound?

Purchase only from licensed dealers authorized to legally export to overseas buyers.

Authentic swords are not modern weapons.

They are historical works of art.