Ninjatō

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Ninjatō (忍者刀) is a short Japanese sword often pictured as the weapon of the ninja, but solid evidence for its existence before the 20th century is lacking.

What it’s like: a short, single-edged blade about 46 cm (around 18 inches) long, with an overall sword length near 48 cm (about 19 inches) and a square guard. The blade is typically straight and fairly thick.

Historical reality: there’s no proven antique ninjatō from the Sengoku period or earlier that matches the popular image. Many swords sold as ninjatō are modern or based on designs from wakizashi, chokutō, or infantry swords used by ashigaru.

Modern descriptions: some ninjutsu teachers, like Masaaki Hatsumi and Stephen K. Hayes, discuss the weapon in detail, but these accounts aren’t strongly supported by ancient evidence. Theories include that straight blades were easier to forge, or that ninjas drew on imagery of a straight-bladed deity, Fudo Myo-oh.

How it’s imagined in use: usage is largely speculative. In films and stage shows, the ninjatō is shown as shorter than a katana with a straight blade, used with fast draw-and-cut or thrusting techniques, sometimes with a reverse grip.

Other notes: stories about the scabbard include uses as a snorkeling tube or for hiding items, and sometimes the scabbard is said to be longer than the blade to conceal things. Some accounts describe a large, square tsuba (hand guard), and a tale that the guard could help extend reach if used as a stepping point.

In 2025, the British government banned possession, manufacture, import and sale of knives deemed “ninja swords,” describing most banned weapons as having a blade between 14 and 24 inches with one straight edge and a tanto-style point.