The tachi is a Japanese sword, normally wielded by cavalry troops due to its length, which can be up to 4 feet in some cases. This sword differs from its direct ancestor, the chokuto in that it has a narrow blade with a single edge, and is highly curved, apparently making it easier to draw from the scabbard in one motion. Tachis also usually had a metal band or hole in the butt of the hilt called a kashira so that a cord could be attached and wrapped around the wrist

These blades were in common use between 800-1200 A.D., before a change in military tactics led to the creation of the katana