The ninja sword is commonly referred to as the ninjato or ninjaken. However, it's important to note that the historical accuracy and existence of a specific sword exclusively associated with ninja warriors are subjects of debate among historians and experts.

The term "ninjato" is often used to describe a straight-bladed, shorter sword associated with the ninjas, which is distinct from the curved and longer katana commonly associated with samurai. The ninjato is believed to have been a practical weapon for covert operations, allowing for stealthy movements and quick strikes in close-quarters combat.

However, it's worth mentioning that historical evidence of a specific ninjato sword with consistent design and characteristics is limited. The popular depiction of the ninjato as a unique and specialized weapon used exclusively by ninjas is influenced more by fictional works, movies, and modern interpretations rather than historical records.

The actual weaponry used by ninjas would have varied depending on the era, region, and specific mission requirements. They would have utilized a range of common weapons available during their time, including various types of swords, daggers, and other tools adapted for stealth and espionage.

In summary, while the term "ninjato" is commonly used to refer to the ninja sword, its historical accuracy and existence as a distinct weapon are uncertain, and the actual weaponry used by ninjas would have been diverse and adapted to their specific circumstances.