The bigger version of a katana is known as the "ōdachi" or "nodachi." The ōdachi is a Japanese sword characterized by its exceptionally long blade. It can be considered an oversized or larger variant of the katana.

The main distinction between a katana and an ōdachi lies in the length of the blade. While a standard katana typically has a blade length ranging from 60 to 75 centimeters (24 to 30 inches), the ōdachi's blade can extend well beyond that, often measuring around 90 centimeters (35 inches) or longer. Some ōdachi blades could even reach lengths of over 120 centimeters (47 inches), although those are exceptional cases.

The ōdachi was historically used by foot soldiers and warrior monks in specific historical periods. Due to its size, the ōdachi was often employed in open-field battles, providing an extended reach and powerful sweeping strikes. It was particularly effective against cavalry and multiple opponents.

In terms of handling and technique, the ōdachi is similar to the katana but requires specialized training and a different approach due to its larger size and weight.