Katana Parts

Understanding katana anatomy requires learning authentic Japanese terminology, the only language used by sword collectors, martial artists, and traditional craftsmen worldwide. Every component, from the blade's cutting edge to the handle's ornamental fittings, carries a specific Japanese name that defines its function and cultural significance. This comprehensive guide breaks down all 24 katana parts, teaching you the precise vocabulary and technical knowledge needed to identify, discuss, and appreciate these legendary Japanese swords with expertise.

➜ Click any component name below to access in-depth explanations, historical background, and traditional craftsmanship details for that specific katana part.

1. The Katana blade

The blade is the katana's most critical and valuable component, representing approximately 50% of the sword's total cost. This premium value reflects the complex forging techniques, varied steel types (from traditional tamahagane to modern high-carbon alloys), and differential heat treatment methods required to create an authentic Japanese blade.

A. Nagasa

B. Sori

The Sori measures the blade's curvature, a defining feature that varies between katana styles and historical periods. Different curvature types include Koshizori (deep curve near handle), Toriizori (uniform arc), and Sakizori (curve near tip). This curve enables powerful cutting techniques while allowing rapid drawing from the scabbard.

C. Shinogi & Shinogi-Ji

The Shinogi is the raised ridgeline running along the blade's length, separating the cutting edge section from the flat surface. The Shinogi-Ji refers to the flat plane between this ridge and the blade's spine (Mune). This architectural feature provides crucial structural integrity and creates the distinctive blade geometry that makes katana both resilient and capable of maintaining razor-sharp edges.

D. Hamon

The Hamon is the visible hardening line created through differential heat treatment, a signature innovation of Japanese swordsmithing. By coating the blade's spine with clay before quenching, smiths create a blade with a hard, razor-sharp edge (~60 HRC) and a flexible, shock-absorbing body. This temper line appears in distinctive patterns—from straight (Suguha) to wildly irregular (Midare), making each authentic katana visually unique.

Achieving a perfect Hamon requires exceptional skill and cannot be guaranteed even by master smiths, significantly impacting high-end blade pricing.

E. Boshi

The Boshi refers to the Hamon's hardening line as it extends into the Kissaki (tip section). Master polishers spend considerable time revealing the Boshi, as this area showcases the swordsmith's control over the hardening process at the blade's most critical cutting point. The Boshi pattern, whether it curves back (Kaeri) or ends abruptly (Yakizume), serves as an authentication marker used by experts.

F. Yokote

The Yokote is the distinct angular transition line that separates the main blade from the Kissaki (tip section). This geometric feature, characteristic of most traditional katana, creates a clearly defined point region with its own geometry and hardness properties. While most katana feature a visible Yokote, certain blade styles (particularly unokubi-zukuri profiles) exhibit continuous geometry without this demarcation.

G. Kissaki

The Kissaki is the blade's point section, beginning at the Yokote line and extending to the tip. Kissaki size varies significantly, from small (Ko-Kissaki) to elongated (O-Kissaki), reflecting different historical periods and combat styles. Tip condition is crucial for katana valuation, as damage severely diminishes both functionality and collectible worth.

H. Ha

The Ha is the katana's cutting edge, where geometry, steel quality, and heat treatment converge to create legendary sharpness. Traditional Japanese blades achieve edge angles between 10-15 degrees while maintaining durability through the Hamon's differential hardening.

The Ha's grind angle, polish quality, and hardness level determine cutting performance, from slicing through bamboo mats (tameshigiri) to maintaining sharpness through extended use. Proper maintenance ensures the blade remains razor-sharp and durable for generations.

I. BO-HI

The Bo-Hi is a longitudinal groove carved into the blade, serving multiple functional purposes beyond simple weight reduction. While decreasing mass, its primary benefits include rebalancing the katana's pivot point, reducing blade inertia for faster techniques, and producing the characteristic "tachikaze" (sword wind sound) that provides auditory feedback during cuts.

The Bo-Hi's depth and width are carefully calculated, improper groove dimensions can weaken the blade or negatively affect handling.

J. Nakago

The Nakago is the tang, the blade extension that inserts into the handle, serving as both the sword's historical record and structural foundation. Master smiths inscribe their signatures (Mei), creation dates, and sometimes ownership records on the Nakago, making it invaluable for authentication.

The tang's geometry, length, and peg hole (Mekugi-ana) positions determine how securely the blade seats and how forces transfer during cutting. The Nakago's surface patina and file marks (Yasurime) provide crucial information about the blade's age and history.

2. Katana Scabbard

A. Saya

The Saya is the katana's scabbard, precision-engineered from lightweight wood (traditionally Honoki magnolia) to protect the blade while enabling lightning-fast deployment. The internal dimensions achieve a perfect friction balance, secure enough to prevent accidental sliding, yet loose enough to allow instantaneous drawing (nukitsuke).

High-quality saya feature lacquer finishes in traditional styles like Ishime (stone pattern) or polished black, with some including brass or horn reinforcements at stress points. The wood naturally absorbs moisture, preventing rust without damaging the blade's polish.

B. Shitadome & Kurigata

The Kurigata is a small knob protruding from the saya's outer surface, serving as the attachment point for the Sageo cord. The Shitadome is a decorative cap that reinforces the Kurigata while preventing the cord from damaging the scabbard's finish.

Together, these components enable traditional carrying methods where the Sageo secures the katana to the wearer's obi (belt), keeping the weapon instantly accessible while preventing loss during movement.

C. Sageo

The Sageo is a braided cord that secures the katana to the wearer's belt, serving both practical and ceremonial functions. Materials range from silk and cotton to leather, with traditional braiding patterns adding strength and aesthetic appeal.

The Sageo's color traditionally coordinates with the Tsuka-Ito handle wrapping. Proper tying techniques, from basic knots to elaborate methods, constitute an essential skill in Japanese swordsmanship etiquette.

3. Between the handle and the blade of katana

A. Habaki & Seppa

The Habaki is a metal collar that wraps tightly around the blade base, creating the precise friction fit that locks the katana securely in its saya. This component produces the distinctive "kachi" sound when drawn or sheathed, indicating correct tension.

Beyond retention, the Habaki prevents moisture and contaminants from entering the scabbard while reducing shock and vibration during cutting. Traditional Habaki are crafted from copper or brass, often featuring fire-gilding or embossed designs.

Seppa are thin metal spacers (typically two) positioned on either side of the Tsuba guard. These washers eliminate gaps in the assembly, ensuring tight, rattle-free construction while absorbing impact forces during cuts. Properly fitted Seppa are essential for professional-quality sword assembly.

B. Tsuba

The Tsuba (handguard) protects the hand from opponent strikes while preventing the wielder's hand from sliding onto the blade during thrusts. Beyond protection, the Tsuba serves as a counterweight that fine-tunes the katana's balance point.

Historical Tsuba evolved into supreme metalwork art, ranging from simple iron circles to elaborate pieces featuring gold inlay, relief carvings, and symbolic imagery representing family crests (mon) or legendary scenes. The central opening (Nakago-ana) is precisely shaped to fit specific blades.

4. Katana Handle

A. Fuchi

The Fuchi is a metal collar that reinforces the handle's forward end, preventing wood splitting under impact while concealing internal construction. Traditional Fuchi feature intricate metalwork in shakudo (gold-copper alloy) or carved iron, often forming matching sets with the Kashira pommel. Common motifs include dragonflies (symbolizing victory), dragons, geometric patterns, and family crests.

B. Tsuka-Ito

The Tsuka-Ito is the braided wrapping that covers the handle, providing grip texture while securing all components into a unified assembly. Traditional wrapping uses flat silk, cotton, or leather cord applied in specific patterns, primarily Hineri-maki (twisted) or Hira-maki (flat) styles.

Modern alternatives include polyester and suede for moisture resistance. The diamond-shaped gaps (Hishigata) formed by proper wrapping should be uniform and aligned, demonstrating skilled craftsmanship.

C. Same

The Same refers to ray or shark skin panels that cover the wooden handle core, providing the foundation for the Tsuka-Ito wrapping. Genuine Same features calcified nodules (called "pearls" when polished) creating a naturally non-slip surface even when wet.

These nodules prevent the wrapping from sliding or loosening over time while providing impact absorption. Premium Same features large, uniform nodules, particularly the central "crown pearl" (hon-Same), which commands premium prices.

D. Mekugi

Mekugi are bamboo pegs that pass through the handle and corresponding holes (Mekugi-ana) in the tang, mechanically locking the blade into the assembly.

While the handle's friction fit provides primary retention, the Mekugi serve as critical safety backups preventing blade loss during vigorous techniques. Traditional katana often feature two Mekugi for redundancy.

Regular inspection and replacement is essential maintenance, as dried-out or damaged pegs can fail during use.

E. Menuki

Menuki are ornamental plaques positioned under the wrapping, visible through the Ito's diamond gaps. Beyond decoration, their raised profile creates palm pressure points that improve grip control and reduce fatigue during extended practice.

Traditional Menuki depict warriors, mythological creatures, or nature scenes, crafted from shakudo, shibuichi (silver-copper alloy), or precious metals with patination or gilding techniques.

F. Kashira

The Kashira is the pommel cap that seals the handle's end, compressing and securing all components while preventing moisture from entering the wood core. The pommel also serves as an impact weapon (tsuki techniques) in close-quarters combat.

Kashira typically form matched sets with the Fuchi collar, featuring complementary designs and metalworking. Traditional shapes include round (maru-gata), onion-shaped (kurikata), or squared forms, with surfaces displaying polished metal to elaborate relief carvings.