Armor and Swords — How Tachi, Katana, and Wakizashi Were Carried and Used

What is Shogusoku—The Positioning of Swords in the Armor System

Shogusoku refers to the collective term for small protective equipment and weapons that samurai of the Sengoku period carried alongside a full set of major armor (daigusoku) when wearing kacchu. Specifically, in addition to small protective gear such as kote, suneate, and haidate, it included swords such as koshigata, uchigatana, and wakizashi.

Understanding the concept of shogusoku is essential to understanding how Sengoku samurai actually carried and used swords. Scenes in movies and period dramas where an armored samurai smoothly draws an uchigatana are often quite different from actual battlefields. When bearing heavy kacchu, there were physical constraints on drawing and using swords, leading to the development of specialized carrying methods adapted to battlefield use.

Koshigata—The Primary Sword During Armor Wear

The swords that armored samurai primarily used on the Sengoku battlefield were often koshigata rather than uchigatana. Koshigata refers to relatively short swords with a blade length of approximately 30-60 cm, which in modern classification are close to tanto or wakizashi, and were hung down from the waist (kusazuri) of the kacchu or worn at the side.

When wearing heavy o-yoroi or touseigusoku, drawing a long uchigatana (blade length 60 cm or more) was difficult. This is because various parts of the kacchu restricted arm and body movement. Therefore, in close-quarters combat (kumitachi), short and easy-to-handle koshigata were advantageous for defeating enemies. To target the gaps in the kacchu—the underarms, neck, and head—tanto-type koshigata suited for thrusting techniques made sense.

One type of koshigata is the yoroizutoshi (armor piercer). This is a short, thin sword specialized in killing enemies by stabbing through gaps in kacchu. The blade was double-edged or single-edged and designed more for thrusting than cutting, and the handle was designed to be gripped comfortably while wearing kote.

Uchigatana on the Battlefield—Close Combat vs. Open Fields

The uchigatana is a sword worn at the waist in its scabbard. The blade length is generally 60-75 cm, shorter than tachi and longer than wakizashi.

Although uchigatana were used during the Sengoku period, they were more commonly employed by unarmored ashigaru or lightly armed samurai on open battlefields rather than by heavily armored samurai. Without armor, the mobile drawing of uchigatana was effective.

From the late Muromachi period into the Sengoku period, collective pike-armed ashigaru tactics developed, and combat became dominated by densely packed pike formations (yarigasumi) rather than individual sword skills. With these changes in warfare, the role played by uchigatana on the battlefield often remained supplementary, secondary to bows, spears, and firearms.

Wakizashi—The Development of Two-Sword Pairing and Its Meaning Outside the Battlefield

Wakizashi are shorter swords (generally with blade lengths of 30-60 cm) carried in combination with uchigatana, and in the Edo period, this two-sword pairing became institutionalized as the formal dress of samurai. However, during the Sengoku period, the concept of wakizashi was not yet established, and rather, various short swords were distinguished and used according to circumstances.

The systematization and institutionalization in the Edo period of samurai sword-wearing into the two swords (uchigatana and wakizashi) reflected political intentions of weapons management. The shogunate's intention was to make samurai status visible through swords and maintain social order by establishing certain standards of armament.

From Battlefield to Edo City Streets—Historical Transformation of Carrying Methods

In the transition from the Sengoku period to the Edo period, the form of samurai sword-wearing changed dramatically. The shift from koshigata-centered battlefield sword-wearing, adapted to heavy kacchu, to the two-sword pairing as formal dress in peaceful urban society symbolized not merely a change in sword form, but a fundamental transformation in the nature of samurai themselves.

The sword transformed in social meaning from a "tool for killing and wounding" to "the samurai's soul and proof of status," and the method of carrying it also reflected this change. When considering the Japanese sword in the modern era, keeping in mind this duality of practical utility as a weapon and symbolism as a social emblem leads to a deeper understanding of Japanese sword culture.