The ōdachi, also known as nodachi, is a Japanese sword characterized by its long blade. The exact length of an ōdachi can vary, but typically, it falls within the range of approximately 90 centimeters (35 inches) to 120 centimeters (47 inches) in blade length.

It's worth noting that the length of an ōdachi is generally longer than that of other Japanese swords such as the katana or tachi. The extended length of the ōdachi allows for greater reach and striking power, making it suitable for wide, sweeping cuts and battlefield use.

However, it's important to recognize that the measurements can vary depending on the specific sword, historical period, and individual preferences. Some exceptionally long ōdachi blades could even exceed 120 centimeters (47 inches) in length, but those are rare and considered outliers.

Overall, the ōdachi is known for its long blade, and its size and weight necessitate specialized training and techniques for effective use.