Shinobigatana is a sword which is said to be used by ninja and is also called Ninjato.
The size and shape of Shinobigatana are designed to improve the portability and functionability compared with swords used by Samurai.
Most "Shinobigatana (Ninjato)" currently transmitted have a length between an ordinary Uchigatana and a wakizashi (short sword) and are classified into Nagawakizashi (long wakizashi). It has only slight warpage unique to Japanese swords and the body of the blade is classified into "Straight sword."
The sword-guard is large and angular, and the shitao (string) is longer than that of an ordinary sword; the sheath is matted so that it does not glitter when light reflects off its surface, and the tip of the sheath is made of metal, and forms an acute angle.
Rules of use
The sword guard of Shinobigatana is large and angular, and it was used as an alternative of a ladder to put foot on it. Generally, a sward has a piece of string called shitao on the scabbard and the string of Shinobigatana is longer than that of the ordinary sword and the string was used to collect the sword after it was used as an alternative of a ladder of 1 m,. The scabbard of Shinobigatana is coated in black and frosted to prevent reflection and make it inconspicuous. The kojiri at the tip of the scabbard is made of metal and acute angled so that it can be driven into the ground or used as a weapon. Some kojiris are removable and used to contain medicines, etc. and it is said that a cylindrical scabbard was used like a snorkel to hide under water. However, the scabbard is physically too long to be used as a snorkel, so breathing is difficult unless they have a very large lung capacity. Therefore, it is now believed that the method was not used actually (such scabbards might be disassembable but do not exist currently).
There is a technique called "Zasaguri no Jutsu" as a fighting method using ninjato. When they fight in the dark, they locate enemies by hooking the scabbard on the tip of the sword. Since it is hooked on the tip, the length is naturally doubled. Then the end of the shitao is put into the mouth. When the tip of the sheath is struck on an enemy and removed or when the enemy cuts away the sheath, they move straight forward and stab. The sheath is blown off, but the shitao is put in the mouth, so the sward can be collected even in the dark.
Actually, Ninja minimized chances of direct fighting. The shinobigatana is shorter and less curved than the ordinary sward used by samurai and the cutting performance is inferior. Except extremely narrow places, it is obviously disadvantageous to use shinobigatana if the enemy was a very close rival.
Consideration about existence
Although the swords called "Shinobigatana (Ninjato)" exist, there is a theory that says that it is doubtful whether Ninja actually were equipped with swords of this shape. If those who carry out their missions secretly under the cloak of common people carry such specially-designed swords, they attract public attention all for nothing. In ninja art books, such as Ninhiden or Shukai BANSEN, there is no description of shinobigatana, but a description that "use thick and wide wakizashi and uchigatana and put them not to break (after the Edo period, common people other than samurai were allowed to carry wakizashi for self defense or revenge if they made registrations at public offices). At almost all ninja schools, except the Iga school and Koga school, they did not use such special swords, but used Wakizashi and Uchigatana. Most existing swords are said to be made for displays at tourist facilities after the Meiji period.
There are several stories about the existence of "Shinobigatana (Ninjato)": They were actually produced, but held as the symbol of rebellion against the Tokugawa bakufu, or it was exaggerated in the Futaro YAMADA's library work, "Ninpocho"series, and its image was established.
Until now, may or may not be true, "Ninja" that appear in movies or other works carry this "Shinobigatana" and mock swords produced for ornamental use are sold as souvenirs at tourist spots or as props for plays or Kosupre (costume play) or replicas for collections.