Ninjaken

The Ninjaken (also called shinobigatana) is an alternative name for “ninjato,” or the sword a ninja would have carried. The typical shinobigatana carried by a ninja would most likely have been a wakizashi or cut-down katana, perhaps even an aikuchi or most likely a chokuto fitted with a katana-length handle and placed in a katana-length saya (scabbard). This may have been used to deceive one’s opponents into miscalculating how quickly it could be drawn, allowing one to use a battoujutsu strike faster than expected. It also disguises the weapon (that would easily identify them as a ninja) as a common sword.

The extra space in the saya may also be used to store or hide other equipment or goods. Of course, a shorter blade forces the fighter to get closer to his opponent, which may be a disadvantage or an advantage when facing an opponent armed with full length swords, or in an iai duel when, to enhance chances of striking first, you’d draw as soon as your blade’s length allowed, and make full use of its slashing ability, while a shorter blade tends to be used in more of a stabbing style.

However, most authorities believe the shorter blade to be an advantage in terms of concealment- the Ninja would have avoided conflict to begin with, and spend a lot of time hiding in small places- and more importantly better suited to indoor combat; If the spy was revealed, the assassin discovered, and it came to a fight, then a shorter, straighter blade would serve the Ninja better in close quarters. Corridors, for example, would seriously hamper a Samurai using a Katana, or several using wakizashi, to say nothing of ceiling clearance on a down stroke/slash.