The dagger-like companion to the katana is commonly known as a "tanto." The tanto is a traditional Japanese dagger characterized by its single-edged, straight or slightly curved blade and typically measuring around 6 to 12 inches in length. It was historically used by samurai as a secondary weapon, often in close-quarters combat or as a tool for personal defense.

The tanto has a distinct design that sets it apart from the longer and more curved blade of the katana. While the katana was primarily used for slashing and cutting, the tanto excelled in thrusting and stabbing attacks due to its shorter and sturdier blade. It was useful in situations where a shorter weapon was advantageous, such as in confined spaces or for precision strikes.

Tanto blades were often forged with the same care and craftsmanship as katanas, using high-quality steel and undergoing a similar heat treatment process. The hilt and fittings of a tanto could vary in style and materials, reflecting the tastes and preferences of the owner.

Today, tanto knives continue to be popular among collectors, martial arts practitioners, and enthusiasts of Japanese weaponry. They are admired for their aesthetic appeal and historical significance, and modern tanto-style knives are also produced for various practical purposes, such as self-defense or general utility.