Ninja-tō is more of a concept than a strictly defined weapon. It means a sword that has been disguised or modified to look like something else, or a tool, weapon or object that has been modified or disguised to look like a sword. For example, these could include a staff that has a blade hidden inside it (shinobi-zue), or a saw that has been disguised to look like a sword.

Togakure-ryu -school includes kata practices that utilize a shinobigatana. In this case, the item in question is a sword with a blade that is shorter than normal and a sageo - or scabbard cord - that is longer than usual. It was also not uncommon to attach a weight (fundo) to the end of the sageo. The saya or scabbard of the sword was, however, of normal length, providing a false perception of the length of the sword. The purpose of the shinobigatana was to not draw attention, appearing outwardly like a normal katana. The straight-bladed sword with a square guard (tsuba) sometimes seen in movies and video games is likely a modern fictitious invention.

There are other traditional sword schools which prefer a shorter sword in their practice.