A "double edge katana" is a term that can be somewhat misleading or confusing because the traditional katana, as commonly known, has a single-edged blade. The term "double edge" typically refers to a sword with two sharpened edges, like a double-edged dagger or a European-style sword.

However, it's worth noting that there are some rare historical variations of Japanese swords that had double-edged blades, but they are not commonly referred to as katanas. For example, the "nodachi" is a larger two-handed sword with a long, curved, and double-edged blade. The nodachi was primarily used by warriors on foot and was known for its cutting power. However, it's important to recognize that the nodachi is distinct from the more common katana.

In summary, while there are some exceptions and historical variations, the term "double edge katana" is not commonly used to describe the traditional single-edged katana. The katana is renowned for its single-edged blade, curved shape, and specific design characteristics that set it apart from other types of swords.