The terms "odachi" and "nodachi" are often used interchangeably to refer to a large Japanese sword with an exceptionally long blade. However, it's worth noting that the usage and distinction between the two terms can vary depending on the source or historical period. Here are a few common ways in which the terms odachi and nodachi are sometimes differentiated:

1. Etymology: The terms "odachi" and "nodachi" both translate to "large sword" in Japanese. However, some sources suggest that "nodachi" is an older term, while "odachi" became more commonly used in later periods.
2. Historical Usage: Some sources differentiate between the terms based on their historical usage. According to this perspective, an "odachi" refers to a large sword primarily used by foot soldiers on the battlefield, while a "nodachi" was a ceremonial or symbolic sword carried by samurai for special occasions or as a display of status.
3. Blade Length: Another distinction that is occasionally made is related to the length of the sword. Some sources propose that an "odachi" has a blade length of around 90 centimeters (35 inches) or longer, while a "nodachi" refers to an even longer sword with a blade length exceeding 120 centimeters (47 inches). However, these measurements can vary, and the differentiation based on blade length is not universally agreed upon.

It's important to note that terminology and definitions can differ, and there is no universally accepted consensus on the precise distinction between odachi and nodachi. The usage of these