A "daito" sword, also known as "tachi," refers to a type of Japanese sword that was primarily used by samurai during the earlier periods of Japanese history. The term "daito" translates to "long sword" in English.

Daito swords typically have a curved, single-edged blade with a length of around 70 to 80 centimeters (27 to 31 inches). They were designed to be worn suspended from the samurai's belt with the cutting edge facing downward, which facilitated their quick draw from a standing position. Daito swords were primarily used on horseback and were effective for both cutting and thrusting attacks.

Compared to later-developed swords like the katana, daito swords had a slightly longer handle and a more pronounced curvature. They were designed for use with two hands, providing the samurai with better leverage and control during combat. Daito swords were often forged using traditional techniques and high-quality materials, showcasing the craftsmanship and artistry of Japanese sword-making.

Over time, the term "tachi" became more commonly used to describe this type of sword, while "daito" is less commonly used. However, both terms generally refer to the same style of sword—long, curved, and primarily used by samurai during earlier periods of Japanese history.