Japanese Sword Polishing (Kanzan)

Introduction to Blade Polishing
 
Blade polishing is one of the most important crafts in the history of metal weapons. From ancient bronze swords to modern steel knives, polishing determines not only sharpness but also appearance, balance, preservation, and spiritual value.
 
In Europe, sword polishing emphasizes symmetry, luster, and cutting performance, using water stones, oil stones, and mechanical grinding. Chinese swords focus on smoothness, engraving coordination, and ancient charm. Middle Eastern daggers and Persian swords pursue high gloss and Damascus pattern display. Each polishing system represents the wisdom and aesthetics of different civilizations.
 
Among all blade polishing techniques, Japanese sword polishing (Togi) is recognized as the most rigorous, delicate, and complete system in the world. It is not simply sharpening, but a traditional craft that restores the sword’s original shape, reveals its texture, Hamon (temper line), and grain, and gives the sword life.
 
Introduction to Japanese Sword Polishing
 
Japanese sword polishing, known as Togi, is a professional technique passed down for hundreds of years. A master polisher (Togishi) does not sharpen blades but “awakens” the sword. Through multi-stage grinding with natural stones, the polisher restores the correct geometry of the blade, shows the Hadori (blade pattern), Hamon, and Ji-hada (surface grain), and presents the highest beauty of the Japanese sword.
 
Polishing a single sword often takes one to three weeks or longer, completely by hand, without any power tools. This is the unique charm of Japanese sword polishing.
 
How a Master Polisher Works
 
A real togishi is strict, patient, and respectful to the sword. Before polishing, he will check the blade’s condition, repair defects, confirm the original shape, and formulate a complete stone sequence.
 
He uses only natural whetstones and clean water, grinding at a fixed angle with even strength. Every movement is stable and consistent. He does not pursue speed but precision and balance. For a master, polishing is a kind of practice.
 
1. Types of Whetstones (Toishi)
 
Japanese sword polishing uses a complete set of natural whetstones, divided by grit and function:
 
- Ara-to: Coarse grinding stone, for removing rust, reshaping, and correcting major damage
- Chuu-to: Medium grinding stone, for shaping the blade geometry
- Komi-to: Fine medium stone, for smoothing surface scratches
- Uchigumori: Hard fine stone, for preparing the final finish
- Nagura: Small rubbing stone, used to create slurry and enhance pattern visibility
 
Stones are selected strictly by hardness, texture, and cutting ability.
 
2. Shiage-to – Finishing Whetstones
 
Shiage-to is the highest-class natural whetstone for the final polishing stage. It has extremely fine particles and is used to show the Hamon, Ji-hada, and luster of the blade.
 
Common types include:
 
- Rengeishi
- Nakaishi
- Rokuyamaishi
- Ohishi
 
These stones are rare, expensive, and critical for achieving the mirror-like final appearance.
 
3. Complete Stages and Process of Polishing
 
Japanese sword polishing is divided into several core stages, performed in strict order:
 
(1) Shitaji-ken (Underpolishing / Rough Grinding)
 
The first stage: Use coarse to medium stones to remove old rust, dents, and deformation. The polisher corrects the overall shape of the blade, including the length curve, width, and cross-section.
 
(2) Shitaji-ken (Secondary Underpolishing)
 
Continue with finer medium stones to eliminate deep scratches, establish the correct blade geometry, and prepare for fine polishing.
 
(3) Shiage-ken (Finishing Polishing)
 
Use high-class natural finishing stones to polish the surface smoothly. This stage brings out the texture of the steel and the clarity of the Hamon.
 
(4) Boku-nuke (Wiping & Cleaning)
 
After polishing, use clean cotton or special cloth to wipe the blade, remove stone dust and moisture, and enhance luster.
 
(5) Ha-tori (Edge Setting)
 
Precisely grind the cutting edge (Ha) to form a sharp, durable edge with correct angle. This step determines sharpness and durability.
 
(6) Kashi-tori (Kissaki Polishing / Tip Polishing)
 
Grind the Kissaki (sword tip) with extreme care. The shape, curve, and Hamon of the kissaki are the most difficult parts of the sword. A perfect hatamoto (tip shape) reflects the master’s skill.
 
Illustrated Diagram Description
 
The standard Japanese sword polishing diagram includes:
 
1. Whetstone classification chart (coarse to finishing)
2. Polishing angle diagram for blade surface
3. Ha-tori edge grinding diagram
4. Kissaki grinding structure diagram
5. Before-and-after comparison of polishing
 
These diagrams show the professional system of Japanese sword polishing intuitively.