An ōdachi (大太刀) or nodachi (野太刀) is an exceptionally large Japanese sword, often exceeding 90 cm in blade length, designed for battlefield use. The name ōdachi translates to “great tachi,” while nodachi means “field tachi,” though both terms are often used interchangeably. This weapon was primarily wielded by foot soldiers and was designed for cutting through cavalry, enemy formations, and armor.

Sugata (姿, Blade Shape)

• The ōdachi retains the deep koshi-zori (腰反り, curvature near the tang) characteristic of a tachi, but with an even longer and more exaggerated curve.
• The blade can range from 90 cm to over 150 cm, with some ceremonial or offering swords reaching even greater lengths.