Tachi Sword Complete guide to understand


The Tachi is the predecessor of Uchigatana, which is the Katana we all familiar today. Under the current laws, tachi is defined as having a blade length of more than 60 cm. Historically, it appears that many are around 2 shaku and 5 sun (approximately 75 cm) in length. Those that are over 3 shaku (approximately 90 cm) are referred to as "o-tachi" or great tachi. The tachi emerged after the Heian era and is characterized by a relatively large curvature in the blade. It is worn using a cord called a tachi-ito, made from leather or similar material, and is suspended from the waist. In this passage, we will explain the history of the tachi, its differences from the uchigatana (a type of shorter sword), and variations depending on its length.

History of the Tachi

The term "tachi" is derived from the Japanese word "tatsu," meaning "to cut," and the weapon was designed with the intention to cut, rather than stab or thrust. Let's trace the evolution of the tachi over the ages.

Heian Era to Early Kamakura Era
Before the Nara period, straight, double-edged swords and single-edged straight swords called "tachi" were mainstream. These were weapons designed for thrusting and stabbing, but as combat tactics shifted from infantry to cavalry, a need arose to increase the striking power from horseback, leading to the introduction of a curvature in the blade. An example of a tachi that evolved from the straight-bladed tachi is the "kenuki-gata tachi," thought to have been influenced by the "warabiteto," a sword that made its way into Japan from the northern region. The kenuki-gata tachi appeared around the middle of the Heian period and is considered the prototype of the Japanese sword. Although its blade still has a slight curve, its shape overall has a pronounced curvature due to the curvature originating from the habaki (metal collar), and the small tip was designed to be able to penetrate the gaps in armor, already reflecting the functional beauty of the Japanese sword.

Mid to Late Kamakura Era
By the middle of the Kamakura period, Japan was in the heyday of the samurai society, and the shape of the tachi changed to reflect a robust samurai style. Previously slender blades became broad and had plenty of meat, transforming into a robust sword that could even cut through heavy samurai armor. Although the blade curvature still originates from the waist, it started to appear as though the entire sword was curved. By the late Kamakura period, the tip of the sword became elongated, the sword itself became slender, and a curvature toward the tip (middle curvature) was added, causing the protrusion of the tip to become prominent. This change is thought to be associated with the transition from horseback combat to group combat after the experience of the Mongol invasions in the middle period.

Nanboku-cho Era to Early Muromachi Era
Eventually, the entire nation plunged into the era of the Northern and Southern Courts, where samurai fought against each other across the north and south. With the increase in infantry due to group combat, "o-tachi" or large tachi were introduced to mow down the enemy. The o-tachi, also known as "shoulder-carried tachi" or "field tachi," had lengths reaching 3 to 5 shaku, and they became a brief trend. In the early Muromachi period, the tachi length settled back to around 2 shaku 5 sun, with a slender width, high curvature, and overall resemblance to the tachi of the Kamakura era. However, the distinguishing feature is a thick blade with the center of curvature closer to the tip, known as tip curvature.

Late Muromachi Era
With the transition to group combat, there was a surge in demand for swords that could be easily handled by infantry. By the late Muromachi period, instead of the tachi which was worn suspended from the waist, the uchigatana, which was inserted into the waist belt, became the main weapon. The uchigatana had a slightly shorter and lighter blade that was easy to carry, so it became the mainstream among soldiers and infantry, gradually increasing its production numbers. However, the tachi did not disappear; commanders would carry a tachi while soldiers on the battlefield preferred the easier-to-handle uchigatana. The large tachi made during the era of the Northern and Southern Courts were polished and re-purposed into uchigatana from this time onward.

The Tachi and Uchigatana: The Differences
When you want to customize a Japanese katana, many people imagine the sword worn on the waist (uchigatana). But sometimes, you might also hear about the "tachi" and wonder if there's a difference. Let's discuss these differences, including the length, era of appearance, and how they were worn.

Length of Tachi and Uchigatana
It's nearly impossible for a layman to distinguish between the tachi and uchigatana based on length. By law, a sword is defined as a blade longer than 2 shaku (approximately 60cm), and both tachi and uchigatana fit this definition. The tachi generally measures around 2 shaku and 5 sun, while the uchigatana measures around 2 shaku and 3 sun, making it slightly shorter than the tachi. However, exceptions are frequent for both types of swords, so these measurements should only be considered as rough estimates.

Era of Appearance for Tachi and Uchigatana
The tachi and uchigatana appeared in different eras. As discussed in the history of the tachi, the tachi appeared first in the history of Japanese swords, becoming visible from the latter half of the Heian period. The uchigatana, an improved version of the tachi, started to appear from the Kamakura period but didn't become mainstream until the Muromachi period. Therefore, from the latter half of the Heian period to the middle of the Muromachi period, the tachi represented the Japanese sword, and from the latter half of the Muromachi period onward, the uchigatana was the mainstream.

How the Tachi and Uchigatana were Worn
One of the main differences between the tachi and uchigatana is how they were worn. The tachi was suspended from the waist using a cord called a tachi-ito, a process called "ha-ku," meaning "wearing a sword." The uchigatana was inserted into the waist belt. Inserting the sword into the belt is called "tai-to," meaning "carrying the sword on the belt." Hence, expressions like "carrying the tachi" or "tai-to (referring to the tachi)" are incorrect and should be avoided.

Front and Back of Tachi and Uchigatana
Due to the different ways of wearing the tachi and uchigatana, another difference arises. The front and back of the tachi and uchigatana are reversed. As mentioned above, because the tachi is suspended from the waist, its blade is always down. Because the uchigatana is inserted into the belt, its blade is up. Generally, when a sword is worn, the side facing the body is considered the back, and the side facing outward is the front. Thus, when the tip of the sword is held up, the blade of the tachi points to the right, and the blade of the uchigatana points to the left, facing the front. From this difference, the tachi is classified as "ha-mote," and the uchigatana as "sa-mote." When displayed in museums, etc., the tachi is placed with the blade down, and the uchigatana with the blade up. The smith's signature is usually on the front side and the date of manufacture on the back side, but there are many exceptions, making it difficult to distinguish the front and back of the sword and whether it is a tachi or uchigatana based on the signature alone. This, like the length, should be taken as a rough guide.
If you are unsure whether your sword is a tachi or an uchigatana…
Tachi Varieties Based on Length
The tachi has evolved over time, changing in length and thickness, resulting in many types. Here we will introduce the types of tachi based on length.
These are around 2 shaku and 5 sun in length, designed for attacking from horseback. They have a curve and a ridge line (shinogi) made on the flat part of the blade.
Oodachi (Great Sword)
These are long tachi exceeding 3 shaku, initially made to clear many infantrymen. They were so large that they were often carried on the back, hence also called "Back-carrying Tachi." They were also referred to as "Field Tachi" as they were primarily used on battlefields. Sometimes, it seems the blade was drawn while a retainer held the scabbard. These swords, initially intended for warfare, started being made for ritualistic purposes, as offerings at shrines. They can be longer than 9 shaku (approximately 2 meters). As time passed, the blades of the oodachi were often shortened and remodeled into uchigatana, which explains why there are few surviving oodachi.
Kodachi (Short Sword)
Kodachi generally refers to shorter swords (less than 2 shaku), but there is no clear definition. Near the end of the period of the Northern and Southern Courts when oodachi were popular, slightly smaller tachi measuring 2 to 2 shaku and 2 sun were also used. These are also referred to as kodachi. As the blade is shorter, they are not as curved and are closer to straight swords.
Let's Pass on the Charm of the Tachi, the Origin of Japanese Swords, to Future Generations
The tachi, appearing in the Heian period, could be said to be the origin of Japanese swords, boasting a curve and a shinogi. Despite being born over 1,000 years ago, its form has hardly changed from modern Japanese swords, and the technology improved through the turbulent Kamakura period, representing a crystallization of Japanese technique. Of course, old tachi have high value as antiques and art pieces. The history of the tachi is old, often mixed with uchigatana, and for oodachi, there are cases where the blade has been shortened and reworked into another sword, making appraisal often difficult.






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