The tachi is a Japanese sword, which has a strongly curved blade and is longer than a katana. It was used on the battlefield before katana was, so it is considered to be older. The word Tachi translates as "the soul of bushi" (soul of samurai).
When the katana began to be widely used the tachi sword became a court sword for ceremonies. It looks very richly decorated with traditional cord wrappings and a specially designed handle. The length of a tachi blade was around 30.70 inches (about 75cm). The first tachi swords were very long; they reached 12.14 feet (90cm) overall and 7.22 feet (17cm) for the blade. It is believed that they were meant for ceremonies. Because of its length the tachi was a cavalry sword and was mainly worn by horsemen. The strongly curved blade also made it easy to make slicing blows. Even if the tachi is a very long sword it is light enough to be handled with one hand. The tachi had a long enough hilt to hold it with two hands. It was especially useful for warriors who were not riding.
The tachi was worn hung to the belt with the cutting-edge down, unlike the katana which was worn with the cutting-edge pointing upwards. Not all tachi were the standard size. Small ones were called ko-dachi. If the sword was longer than the standard one it was called o-dachi.
The tachi that can be seen in museums have one or more chips along the back of the sword, while the cutting edge looks almost untouched and mirror polished. The experts explain that Samurai made the smallest possible moves with their tachi to kill the enemy. Thus when both swords were about to collide, the samurai both turned their swords and let only the blunt back (mune) of the blades hit one another. The cutting edge was used for finish touches, namely for cutting the human body.