Contemporary audiences think of ninjas as masked assassins armed with smoke bombs and throwing stars. However, this image is a distortion based on the romanticization of ninjas in ancient texts, comic books, and movies. So, what weapons did the ninjas actually use?
Ninjas use swords, knives, spears, bows and arrows, and even firearms for weapons. They also worked with spikes, darts, poisons, explosives, and even modified farm implements when required to be more stealthy.
This article will provide a broad overview of the weapons that the historical Shinobi are known to have used, and will discuss the kind of swords and knives ninjas have, and what kind of armor they wear.
What Kind of Swords Did Ninjas Have?
There were two main groups of the Shinobi based out of the Iga and Shiga provinces of medieval Japan. The Iga and Kōga clans were often hired as spies and were experts in covert operations and guerilla warfare. As descendants of samurai clans, the Shinobi would have been familiar with the samurai weaponry of that era.
The kind of swords ninjas had included the iconic curved sword usually associated with samurai, which was their chief weapon. This was called a katana. Although they are often depicted wielding short straight swords, known as ninjatō, there is no evidence that ninjas used ninjatō.
Katanas and other swords were the weapons of choice for fighters of the era. However, at the time, it was against the law for anyone but a samurai to carry such weapons. Getting caught with a katana would have put a ninja and his mission in peril. So, in many circumstances, ninjas could not carry swords.
As a covert force, ninjas also avoided open engagement where possible. They favored guerilla tactics and were known for their shadowy cloak and dagger operations. It was these secretive aspects of the ninja’s craft that, over the centuries, gave them a near-mythic reputation for invisibility.
For all these reasons, the sword was often a weapon of last resort for the ninja. They also sometimes concealed their swords in scabbards that looked like walking canes.
This made it easy to carry a sword without revealing their identity to their enemies. Where movement was more critical than stealth, they wore their swords diagonally across their backs.
The ninjatō that the ninja is often depicted wielding is based on the wakizashi, a short sword that samurai carried along with the katana. However, although ninjas were known to prefer shorter katanas, there is little evidence they used ninjatō or wakizashi.
There is no record of the ninjatō before the 20th century. In all likelihood, it is just one of many embellishments from pop culture that adhere to the ninja myth today.
What Kind of Knives Did Ninjas Have?
The kind of knives ninjas had were iconic short-bladed weapons, including a sickle called the kama. Modified with a weighted chain, the kama became the even more lethal kusarigama. Another standard weapon was the kyoketsu-shoge, a double-bladed dagger attached to a rope ending in a metal ring.
Their inconspicuous nature was a significant advantage of weapons like the kama, the kusarigama, and the kyoketsu-shoge. The kama, for instance, was a farm implement.
It would have been a familiar sight on farms across the Japanese countryside. So, a ninja carrying a kama was less likely to attract attention than one wielding a katana.
Kusarigama and kyoketsu-shoge were also easily concealable. They could be quickly disassembled to look like everyday farm tools. This allowed ninjas to go about their work clandestinely. Such features made kusarigama and kyoketsu-shoge invaluable on covert operations where discretion was crucial.
Kusarigama and kyoketsu-shoge were also multi-purpose weapons. The chain-end of the kusarigama could be swung at an enemy combatant, giving it an extended range over a conventional knife.
Similarly, the rope of the kyoketsu-shoge could be used to restrain captives, and both the kusarigama and the kyoketsu-shoge were also used to climb walls or trees.
Finally, ninjas also deployed a wide variety of other sharp instruments that were similar to knives but, strictly speaking, were not actually knives. These were multi-purpose weapons, used both in combat and as climbing tools. These weapons include the following:
- Kunai: a short spear
- Ashiko: a set of spikes attached to shoes
- Shikoro: a short double-edged saw
- Tekagi: a claw-like weapon adapted from a tool to rake weeds.
What Kind of Armor Did Ninjas Wear?
The kind of armor ninjas wore was a light chain mail shirt under their clothes called a kusari katabira. On most occasions, they wore no other outer armor. However, when they needed to blend in, ninjas wore both the uniforms and the armor of their enemies.
The most common role of the ninja was in espionage activities. They needed to blend in with their surroundings and not attract attention to themselves.
For this reason, ninjas were masters of disguise. According to the website for the Koka Ninja House, a museum of ninja history in Japan’s Shiga prefecture, ninjas were famous for seven disguises. 
Ninjas would often travel dressed as monks, priests, actors, magicians, and commoners. Such personas allowed the ninja to go about collecting information unobserved. However, this also meant that ninjas often wore no armor other than their lightweight kusari katabira.
Sometimes, the ninja also dressed as their enemies. This might be the case if a ninja were infiltrating an enemy castle at night. Such a disguise would offer a ninja greater protection since it meant they didn’t stand out.
The all-black ninja costume known as the shinobi shozoku derives from Japanese drama of the later Edo era. The color of these costumes symbolizes the invisibility that the ninjas were famous for.
The website of the Ninja Museum of Iga-ryu suggests that, historically, such costumes were navy blue rather than black, since navy blue offered better camouflage than black under moonlight. 
Ninjas used conventional weapons of their time, such as swords and knives, alongside modified everyday tools that were more discreet and served multiple purposes.