The Long Blade — Classifying Nagamaki, Ookanabo, and Odachi

Large Swords of the Nanboku-chō Period

The Nanboku-chō period (1336–1392) was an era when the most diverse forms of large swords emerged in Japanese sword history. Prolonged civil strife and infantry-centered combat tactics generated demand for large piercing and slashing weapons, establishing three major forms: nagamaki, ōnaginata, and ōtachi. These forms overlap considerably in their characteristics, and their classification remains a subject of debate in contemporary sword research.

Definition of Ōtachi (Large Tachi)

The ōtachi is a general term for exceptionally large tachi with blade lengths of 3 shaku (approximately 90 cm) or greater.

Characteristics:

• Blade length of 3 shaku or more (some exceed 5–6 shaku and are called "notachi")
• Constructed like standard tachi (shinogi-zukuri with waist curvature)
• Wielded two-handed on foot or carried across the back
• Uses: frontal assault charges, sweeping strikes from horseback, and psychological intimidation

Notable ōtachi:

• Mikazuki Munechika: One of the Five Legendary Swords (Tenka Goken). Blade length 78.8 cm (below the ōtachi standard but a large tachi)
• Dōji-giri Yasutsuna: National Treasure. A late Heian-period work with blade length around 80 cm

Definition and Form of Nagamaki

The nagamaki is a long-hafted weapon in which the blade and haft are relatively equal in length, typically with a blade of 60–90 cm and a haft of 60–90 cm.

• The name "nagamaki" is said to derive from the long haft wrapped with leather or cloth extending from blade to handle
• It features a shinogi-zukuri blade with a long haft, representing an intermediate form between the ōtachi and naginata
• In peacetime, it was carried with the blade resting on the ground; in battle, it was wielded with both hands
• It appears in battle scroll paintings from the Nanboku-chō to Muromachi periods

Comparison with Ōnaginata (Large Naginata)

The ōnaginata is a form of naginata with a blade longer than standard naginata (60–90 cm or more), with the following key differences from the nagamaki:

In actual extant examples, the forms of nagamaki and ōnaginata often overlap, making classification frequently difficult. Contemporary sword research has advanced the systematic classification of these forms through accumulation of morphological data on surviving examples.

Classification Disputes and Contemporary Research

Classification standards for "nagamaki," "ōnaginata," and "notachi" are not unified even in NBTHK evaluations, and individual pieces are typically assessed based on their morphology, provenance, and tradition.

Recent research employs:

1. Blade-to-haft proportional analysis (metrological analysis)
2. Nakago shape and mekugi-hole placement
3. Cross-sectional form of blade construction

A multi-factor analytical approach combining these three elements has been proposed, advancing objective classification of morphological types.

Extant Examples and Museum Collections

Extant examples of ōtachi, nagamaki, and ōnaginata are dispersed and held in shrines and museums throughout Japan. Notably:

• Kasuga Taisha (Nara): Houses numerous large swords from the Nanboku-chō period
• Itsukushima Shrine (Hiroshima): Ancient and large tachi dedicated by the Heike clan
• Tokyo National Museum: National Treasures and Important Cultural Properties of large swords

Public exhibitions of these pieces provide excellent opportunities for comparative study of their forms.