A pre-katana style Japanese sword
A type of Japanese longsword or tr=nihontō, having a single edge and slight curvature, historically used by samurai and ninja.
A tachi (太刀) is a type of traditionally made Japanese sword (nihonto) worn by the samurai class of feudal Japan. Tachi and katana generally differ in length, degree of curvature, and how they were worn when sheathed, the latter depending on the location of the mei, or signature, on the tang.
A katana (刀 or かたな) is a Japanese sword characterized by a curved, single-edged blade with a circular or squared guard and long grip to accommodate two hands. Developed later than the tachi, it was used by samurai in feudal Japan and worn with the blade facing upward.