A kogatana is a small utility knife that is often carried alongside a traditional Japanese sword, such as a katana or wakizashi. The term "kogatana" translates to "small sword" or "little blade" in Japanese. It typically has a single-edged blade and is stored in a small pocket or slot on the saya (scabbard) of the main sword.

Kogatana serve various practical purposes, such as cutting ropes, performing small tasks, or making minor repairs. They are considered multi-purpose tools and are often used by samurai or swordsmen in historical contexts. Kogatana can be made from various materials, including steel, and may feature a simple handle or no handle at all.

While kogatana are no longer commonly used as everyday tools, they still hold significance within the historical context of Japanese swords and the culture surrounding them. Today, kogatana are primarily seen as collectibles or decorative items, appreciated for their craftsmanship and as complementary pieces to traditional Japanese swords.