Dull katanas are often referred to as "blunt" katanas. A blunt katana is one that has a rounded or flat edge and lacks a sharp cutting edge. Blunt katanas are intentionally designed or modified to have a non-cutting edge for specific purposes or safety considerations. They are commonly used in training, demonstrations, theatrical performances, or for decorative or display purposes.

Blunt katanas may have a thickened or rounded edge, which reduces the risk of accidental cuts or injuries during practice or handling. The edge may be blunted through specific modifications or by intentionally dulling the blade to make it safe for various activities.

It's important to note that blunt katanas are distinct from functional sharp katanas, which have a finely honed and sharp cutting edge. The purpose and use of a katana, whether it is sharp or blunt, depend on the intended activity, training, or display.