Japanese Sword Restoration and Polishing Cost Guide: Cost Estimates by Condition and Craftsman Selection

Japanese Sword Restoration—When to Seek Professional Help

A Japanese sword can last for centuries with proper maintenance, but swords that have been neglected may develop rust, blade nicks, or damaged mountings. These issues can be remedied through proper restoration, though costs vary significantly depending on condition and the required processes.

This article explains restoration costs by type and provides comprehensive guidance on selecting craftsmen.

Types of Restoration and Corresponding Specialists

Japanese sword restoration divides into multiple specialized fields, each requiring different craftsmen:

Polishing (Togigashi) Costs in Detail

Polishing is the most costly and delicate restoration work. The blade polisher uses whetstones to remove rust and surface damage while revealing the blade pattern (hamon) and steel structure (jigane) in their best light.

Types of Polishing Processes

Preparatory polishing (shitaji-togi): The initial stage using coarse whetstones to restore overall blade shape and remove heavy rust and deep scratches.

Finishing polishing (shiage-togi): The final stage using progressively finer whetstones to fully reveal the blade pattern and steel structure. Techniques include "powder finish" (uchiko shiage) and "wiped finish" (fuki shiage).

Edge definition (hatori): A finishing technique that sharply defines the blade pattern outline. Requires master-level skill from experienced blade polishers.

Cost Estimates (by Blade Length and Condition)

Note: Important registered swords or works by Living National Treasures may exceed ¥1,000,000 when commissioned to renowned blade polishers.

Difference Between "Standard" and "Full" Polishing

Standard polishing (preparatory stage only) removes rust and damage to restore the blade's functional condition, but does not fully reveal the beauty of the blade pattern and steel structure. Full polishing is necessary for display and appraisal purposes.

For practical use (iaido or test cutting), standard polishing is often sufficient.

Rust Removal Costs

Costs vary by rust severity, from light surface corrosion to deep pitting.

Surface rust (hyōmensabi): Light surface corrosion on the blade face. Sometimes manageable with powder and cloth cleaning. Professional treatment typically costs ¥20,000–50,000.

Pitting rust (tensabi): Deep rust spots appearing on the blade face. Requires polishing, with costs ranging ¥50,000–200,000 depending on depth and extent.

Widespread rust (hadasabi): Heavy corrosion covering the entire blade face. Requires full polishing process, often exceeding ¥200,000–500,000.

Blade Chip and Break Repair

Blade chip and fracture repair represents the most technically difficult and expensive restoration work.

Minor nicks: Small chips addressed through polishing adjustment. Typically handled as part of polishing with minimal additional cost (¥10,000–50,000).

Large chips (1cm+): Repair through polishing requires blade shortening, necessitating careful assessment of impact on value. Preserving the blade as-is may be the appropriate choice in some cases.

Fractured sword repair (rejoining): Welding fractured blades back together is technically challenging and costly (¥300,000–1,000,000+). Determining whether repair cost justifies the restored blade's value is critical.

Koshirae (Mounting) Repair Costs

Restoration of the koshirae—scabbard, grip, guard, and fittings—is an important restoration specialty.

Scabbard repair: Addresses lacquer loss, cracking, and collar damage (kozuchi). Repair costs range ¥30,000–300,000 depending on scope. New fabrication exceeds ¥150,000–500,000.

Grip rewrapping: Addresses worn or frayed grip cord, then rewraps with fresh material. Typically ¥30,000–100,000, varying by material quality (leather, ray skin, silk cord, etc.).

Guard, ornament, and fitting repair: Metal work restoration costs ¥20,000–200,000+. Pieces by renowned metal workers require consultation with specialists.

Selecting Craftsmen and Specialists

Criteria for Choosing a Blade Polisher

1. NBTHK certification or apprenticeship lineage: Blade polishers recognized by the public interest foundation NBTHK (Society for the Preservation of Japanese Art Swords) maintain verified technical standards.
2. Portfolio verification: Request examples of past work (photos, appraisal certificates obtained).
3. Transparent estimates: Confirm that costs are itemized by process rather than lumped together.
4. Alignment on restoration objectives: Verify the craftsman proposes approaches matching your goals—whether full finishing for display or standard restoration for functional recovery.

Warning Signs of Poor Craftsmen

• Providing blanket quotes without clear process breakdown
• Failure to document before and after photos
• No experience with NBTHK appraisal applications (unsuitable for famous swords)

Conclusion—Restoration as Investment

Japanese sword restoration costs are substantial, yet proper restoration can multiply the blade's value many times over as an investment. For swords by renowned makers or important cultural properties, sparing no expense on top-tier blade polishers preserves long-term value.

Conversely, for functional iaido swords or common production blades, minimal restoration is cost-effective. Clarifying your restoration goal beforehand and selecting craftsmen and budget levels accordingly is essential.