Ōdachi and Nodachi: Forms, Battle Use, and History of Giant Swords from Nanbokuchō to Muromachi

Ōdachi and Nodachi

In the classification of Japanese swords, those with a blade length exceeding approximately 90 cm (approximately 3 shaku) are generally called ōdachi (大太刀) or nodachi (野太刀). Some examples possess a blade length of 150 cm or more and a total length exceeding 2 meters, making them a genre with a distinctly prominent presence among Japanese swords.

Though "ōdachi" and "nodachi" are often not strictly distinguished, ōdachi sometimes refers to large swords made for dedication to shrines or for ritual use, while nodachi carries a nuance of referring to large practical swords actually used in field warfare. In modern sword studies, the two are often treated as nearly synonymous.

The Historical Period in Which Ōdachi Emerged—The Nanboku-chō Conflict

Ōdachi were produced most actively during the Nanboku-chō period (1336–1392). The Nanboku-chō conflict was an era in which the Southern and Northern courts fought continuously across the country for an extended period, and the style of combat was in a transition period from kumigumi (individual duels between mounted warriors) to organized infantryman warfare. During this era, swords displayed the following characteristic changes.

• Extension of blade length: Large quantities of swords with blade lengths exceeding those of ordinary tachi (blade length of approximately 2 to 2.5 shaku) were produced
• Deepening of the curve: Alongside the increase in size, there was a tendency for the sori (反り) to deepen
• Substantial jigane (地鉄): Robustness to withstand prolonged combat was demanded

Swords from the era in which figures such as Kusunoki Masashige (楠木正成) and Ashikaga Takauji (足利尊氏) flourished are particularly rich in ōdachi displaying these Nanboku-chō characteristics.

Usage in Warfare

There are various theories about how ōdachi were used in battle. The principal methods of use that are transmitted are as follows.

Bearing and cutting (katsuigiri): Because the blade was too long to hang at the waist, it was carried over the shoulder and wielded with both hands in combat. It is also said that it was used by infantry to sweep through dense enemy ranks in a manner analogous to the naginata.

Use from horseback: It is also transmitted that mounted warriors took advantage of the long blade to cut down enemies below them. However, actual deployment is thought to have required considerable strength and skill, limiting it to specialized users.

Dedication and ritual use: Oversized examples with blade lengths exceeding 150 cm, too large for actual combat, are believed to have been created from the outset as dedication offerings to shrines and temples or as votive swords for prayers of victory. Many of the extant celebrated ōdachi fall into this category.

Extant Famous Ōdachi

Miike Tenta Mitsuyo (三池典太光世) A tachi with a blade length of approximately 65–66 cm (held by the Maeda Ikutoku Foundation). It is said to be the work of the swordsmith Tenta Mitsuyo from the late Heian to early Kamakura period, and is known as "Daitentō (大典太)", one of the Five Swords Under Heaven. Though shorter than the definition of ōdachi (blade length exceeding approximately 90 cm), it is highly valued as a masterwork that conveys ancient-style vigor through its substantial jigane and deep sori.

Ōdachi by Bizen Osafune Kanemitsu (備前長船兼光) The Bizen swordsmith Kanemitsu of the Nanboku-chō period is known for producing many ōdachi, and examples with blade lengths exceeding 1 meter have been dedicated to multiple shrines. Kanemitsu's ōdachi are notable for their abundant flesh deposits and the activity of the ōnie (大錵).

Dedication Blades of the Ōyamazumi Shrine (大山祇神社) The Ōyamazumi Shrine in Imabari, Ehime Prefecture houses approximately 40% of the National Treasures and Important Cultural Properties consisting of armor and other martial equipment, and houses numerous ōdachi and nodachi from the Nanboku-chō period. Inherited as shrine treasures, many were dedicated by military commanders in prayer for victory in war. The shrine's treasure museum is one of the leading facilities in the country for viewing large swords in person.

Dedication Blades of Isonokami Shrine (石上神宮) The Isonokami Shrine in Nara Prefecture has numerous ancient and medieval swords dedicated to it, including large tachi. It is known as a treasure house of ancient swords and also houses swords of unusual forms such as the shichishitō (七支刀).

"Suriage" and the Transformation of Ōdachi

From the Sengoku period onward, many ōdachi made during the Nanboku-chō period were converted to swords of standard size—uchigatana and tachi—through suriage (磨上げ). Suriage is the process of cutting back the nakago (茎) to shorten the overall length, adapting the blade to a size suitable for carrying and practical use. As a result, ōdachi retaining their original form are rare today, and pre-suriage ōdachi possessing an ubu nakago (生ぶ茎) receive high scholarly and market valuation.

Appreciation Points for Ōdachi

When appreciating ōdachi, it is useful to focus on the following points.

1. Blade length and overall balance: Observe how the depth of the sori and the thickness of the kasane (重ね) are designed in relation to the blade length
2. Uniformity of the jigane: The technical difficulty of forging large blades uniformly is high, and works with minimal variation in the jigane are valued more highly
3. Continuity of the hamon (刃文): Verify that the hamon flows with consistent rhythm across the length of the blade edge
4. Condition of the tang: Confirm whether it has been subject to suriage or is ubu. If it is ubu, the preservation of the mei (銘) is often good as well

Opportunities to see ōdachi in person are rare in the modern era, but institutions such as Ōyamazumi Shrine, Isonokami Shrine, and the Tokyo National Museum regularly display their held large swords. The overwhelming presence generated by the gigantic blade is a facet of the allure of Japanese swords that can only be experienced in person.