A type of Japanese sword. The ootachi (also known as 野太刀, "nodachi") is essentially a katana with a very long blade, often longer than the wielder's height. The best-known examples are probably Sephiroth's Masamune in Final Fantasy VII and the various long sword-class weapons featured in the Monster Hunter series.
The ootachi was a rare weapon. In real life, it was used by men on foot to fight against mounted cavalry, however polearms were much easier to produce and in most cases were more effective in that role. Due to it being an expensive weapon that was difficult to forge, it was seen as proof of a swordsmith's skill and a status symbol for a samurai who carried it.
See also
Nagamaki - the inverse of ootachi where the handle was lengthened instead of the blade
