The tachi is a traditional Japanese sword that was primarily used by samurai warriors during certain historical periods. Here are some of the main uses and characteristics associated with the tachi:

1. Mounted Combat: The tachi was designed specifically for mounted combat. It was worn suspended from the belt with the cutting edge facing down, making it easier to draw and strike while on horseback. The length and curvature of the blade were well-suited for slashing attacks from horseback.
2. Samurai Class Symbol: The tachi was a symbol of the samurai class and their status. It represented the martial prowess, honor, and social standing of the samurai who wielded it. It was considered a weapon of the warrior elite.
3. Battle Weapon: The tachi was used in battle as a primary weapon by samurai warriors. It was effective for both cutting and thrusting techniques, providing versatility in combat situations. Its longer and curved blade allowed for powerful slashes and the potential to deliver devastating cuts.
4. Duels and Single Combat: The tachi was also used in one-on-one duels and single combat scenarios. Samurai would engage in individual combat, testing their skills, honor, and resolve. The tachi's design allowed for precise strikes and swift maneuverability.
5. Ceremonial and Display: Like other Japanese swords, the tachi had ceremonial and display purposes. It was often adorned with elaborate fittings, decorative scabbards, and intricate engravings. The tachi was displayed during formal occasions, processions, or as part of samurai regalia to showcase the warrior's heritage, status, and family lineage.

It's worth noting that the tachi eventually evolved into the uchigatana, which was a shorter and more versatile sword that could be worn both mounted and on foot. The uchigatana later gave way to the more well-known katana during the Muromachi period (14th to 16th century).

The use and popularity of the tachi varied throughout Japanese history, with its prominence declining as warfare and fighting styles evolved. However, its historical significance as a symbol of the samurai and its connection to mounted combat remain noteworthy.