Naginata Hamon and Jihada: Polishing Techniques for Long Blades and the Steel Characteristics of Ancient Naginata

Hamon of Naginata——Morphological Differences from Tanto and Tachi

The hamon of naginata possesses unique constraints and possibilities arising from the blade's length and form. The blade length (the length of the cutting portion) of naginata varied significantly by period.

• Ancient naginata from the Kamakura through Nanboku-chō periods: Most ranged from approximately 60–90 cm in blade length (large naginata exceeded this), rivaling or exceeding tachi in length
• Polished (suriage) examples from the Edo period onward and modern naginata-dō implements: approximately 30–60 cm in length (most surviving ancient naginata were ground down (suriage) in later eras)

Its form is characterized by a distinctive curve called "naginata-zori"—a straight blade section that transitions into a sharp reverse curve.

This form exerts considerable influence on hamon formation. What is particularly observable in naginata hamon is the variation in hamon at the blade's curved section. During hardening, the sharp curve at the blade tip produces a different temperature distribution than straight sections, making hamon patterns prone to variation. Master smiths design their clay application (tsuchiyoki) with understanding of this characteristic, yet controlling hamon in curved sections is considered more difficult than in flat-forged tanto or typical tachi.

Regarding hamon types, naginata exhibits the following tendencies.

• Suguha (straight hamon) and komidaré (small undulating pattern): Beyond the practical difficulty of controlling hamon in challenging sections, these are commonly seen due to the historical emphasis on functional hardness distribution over elaborate hamon aesthetics, reflecting the naginata's original purpose (use in sweeping motions)
• Chōji-midare and gunogumo-no-me-midare: Complex hamon patterns found on high-quality commissioned naginata from the Muromachi period, evidencing intentional artistic craftsmanship

Characteristics of Jihada in Ancient Naginata——Period and Material Relations

The jihada of ancient naginata (those produced before the Edo period) tend to display a coarser itame-hada grain compared to contemporaneous tachi and tanto. This may suggest that in eras when naginata were considered inferior to tachi, higher-quality tamahagane was preferentially used for tachi production, though this remains unconfirmed.

In ancient naginata from the Kamakura and Nanboku-chō periods, characteristic jihada of the Bizen, Yamashiro, and Yamato schools can be observed, and regional attribution can be determined through jihada examination alone.

Large naginata (dainaginata) from the Nanboku-chō period sometimes possess grand jihada comparable to contemporaneous tachi, and combined with their long hamon, they present impressive objects of appreciation. However, most surviving large naginata were ground down (suriage) in later eras and converted into wakizashi or tachi, so completely intact examples of ancient naginata are rare.

Challenges in Naginata Polishing Faced by Togishi

Naginata polishing, despite being "long-bladed" like tachi and uchigatana, presents distinct technical challenges. The primary difficulties faced by togishi (polishers) are as follows.

• Polishing the curved section: The naginata's rear half (near the base) runs nearly straight, then curves sharply toward the tip. The transition zone from straight to curved is technically difficult to address uniformly with a whetstone, and uneven polishing pressure risks blurring the boundary between hamon and jihada. Skilled togishi pay particular attention to this transition, fine-tuning whetstone pressure to maintain overall harmony
• Polishing the point section (equivalent to kissaki): The naginata's tip differs in shape from a sword's kissaki, and the blade orientation differs as well. The polishing pattern for the section equivalent to a sword's bōshi (temper line near the tip) must be appropriately adapted to the naginata's form, and sword polishing techniques cannot be directly applied
• Blade stabilization during polishing: Because naginata are long-bladed, securing the blade during polishing is even more challenging than with tachi. The design of the polishing stand (toiyuke) and the method of supporting the blade are critical, and proper polishing requires specialized equipment and expertise

Due to these special requirements, even today the number of togishi possessing naginata-specialized polishing techniques is limited, making it challenging for sword owners to find qualified practitioners for high-quality naginata polishing.

Appreciation Points and Collecting Considerations for Ancient Naginata

From an appreciation standpoint, ancient naginata offer the following points of interest.

• Form (sugata): The dynamic sculptural beauty created by the combination of straight and sharp curves possesses tension entirely distinct from the linearity of tanto or the uniform curve of tachi
• Jihada: The ground pattern appearing on the wide flat section (hiraji) near the base is particularly impressive, and the broad width allows full observation of jihada patterns—a major attraction of naginata appreciation
• Hamon: Tracing the changes in hamon across the curve is a key aspect of appreciation, and the subtle variations in hamon as it follows the blade's contour on the same blade surface directly evidence the smith's skill

An important collecting consideration is distinguishing ancient naginata from blades converted through naginata-naoshi (naginata-straightening). Naginata-naoshi are naginata ground down (suriage) to the length of uchigatana or wakizashi, retaining no original form, yet they can be distinguished through the characteristic naginata curve and the ratio between base width and point width. While naginata-naoshi possess an intermediate aesthetic between naginata and swords, their value assessment differs from those bearing naginata certification.

Many surviving ancient naginata are designated cultural properties, and examples handed down as votive offerings at regional shrines and temples sometimes lack opportunity for expert examination. Naginata research is a niche field within sword authentication, with few specialists, yet it is an area worthy of deep inquiry due to its unique characteristics.