维基

The Ninjatou (忍者刀), also known as ninjaken (忍者剣) or shinobigatana (忍刀), is the most common name for the katana that the ninja were thought to have carried. It is often depicted as being a short sword, often portrayed as having a straight blade with a square tsuba. There is no historical evidence of the 'ninjatou', and modern depictions of the sword originate from portrayals that were seen in early Hollywood movies.