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The chokutō (literally "straight sword") is the primitive form of Japanese sword that predates the famous curved katanas. It was the main blade in the warrior orbit of ancient Japan and represents the meeting point between techniques forged on the Asian continent and the subsequent indigenous evolution of Japanese weapons.
What exactly is a chokutō?
A chokutō is a Japanese sword with straight blade and usually single edge. It was mainly made and used during the Kofun, Asuka periods, and the first centuries of the Heian period (ca. 3rd–10th centuries AD). Unlike later katanas and tachi, which feature a pronounced curvature, the chokutō maintains a linear geometry that favors direct thrusts and cuts.

Origin and influences
The design of the chokutō is influenced by continental swords, especially the Chinese jian and Korean models. Upon arrival in Japan the technique was adapted: while the jian was often double-edged, Japanese craftsmen developed single-edged versions better suited for forceful cuts and thrusts in hand-to-hand combat. The first chokutō appear associated with kofun tombs and archaeological finds that reflect technical and cultural exchanges with the continent.
Technical and construction features
- Shape: straight blade, generally defined tip, without noticeable curvature.
- Edge: normally single edge; the rear face may be flat or slightly beveled.
- Length: It is usually between 60 and 80 cm of leaf, although it varies depending on the season and function.
- Material and forging: use of early steel rolling and folding techniques to remove impurities; configuration that anticipates practices such as tamahagane in later centuries.
- Handle and guard: wrapped tsuka, simple or absent tsuba in very early examples; lacquered wooden saya for protection.
Manufacturing improved over time: visible patterns on the surface of the steel and rudimentary heat treatments began to appear, a prelude to differential tempering techniques that would define the aesthetics and functionality of later katanas.

Tactical and social use
- Combat context: designed for fighting on foot; It was effective in compact formations and in infantry engagements.
- It was not ideal for cavalry: the evolution towards curved swords (tachi and then katana) responds to the need for cutting blows from the horse.
- Symbol and status: In literary and ritual sources, straight swords appear as objects of prestige and sometimes as sacred antiquities in early chronicles.
Transition to tachi and katana
Between the 9th and 11th centuries a gradual transition is observed: the introduction of curvature and changes in the tempering technique allowed more effective cuts from the saddle and more fluid movements. The chokutō was progressively replaced by the tachi (curved sword used by cavalry) and, later, by the katana as we know it, intended both for fighting on foot and to express social status.
Preservation and current relevance
Today authentic chokutō are rare pieces and highly valued for their historical interest. They are preserved in museums and collections that allow the early metallurgical techniques of Japan to be studied. Furthermore, its study helps to understand the technical evolution that gave rise to the most emblematic weapons of samurai culture.
| Type | Curvature | Period | Typical use | Guideline length |
|---|---|---|---|---|
| Chokutō | Straight | Kofun–Early Heian | Infantry and ceremonies | 60–80 cm |
| Tachi | Curved (pronounced) | Heian–Kamakura | Cavalry | 80–90 cm |
| Katana | Moderate curve | Kamakura onwards | Foot combat and social symbol | 60–75 cm |

Readings and ways to delve deeper
- Archaeological studies on kofun tombs and finds of ancient weapons.
- Research on Asian forging techniques and evolution of differential tempering.
- Comparative analysis between continental swords (Chinese and Korean) and the first Japanese swords.
Exploring the chokutō allows us to understand a key episode in the history of metallurgy and Japanese war tactics: the transformation of an imported straight blade into the curved and symbolic sword that we associate with the samurai.