The history of the Ninja, or Shinobi is hard to trace as very few records were kept. From what is known and passed from generations is that they were not just trained in the art of war, but also in traditional philosophy, including Buddhism, Taoism, Confucianism, and the indigenous Japanese religion of Shinto, which they greatly followed. Nonuse, the art of stealth, was first introduced to Japan in 522 A.D. as a religion practiced by priests. They were not violent people but mystics who gathered and shared information for the ruling classes. It wasn't until 645 A.D. that the priests perfected their fighting skills and made use of their knowledge of nonuse. This was because they found themselves being harassed by the central government and found in necessary to protect themselves. In 794-1192 A.D. the new civilization flourished and with it, a new class of wealthy, privileged families. These families fought with one another in attempts to make or destroy empires. The need for spies, informants and now assassins grew as these families dueled. They were suspicious and jealous of one another and would resort to any means necessary to eliminate any possible threats. Therefore, the practitioners of nonuse were in great demand and with this, the ninja was born. The ninja sword or ninja-to had its advantages over katana. The scabbard for instance was made longer than the sword. The end of the scabbard contained a hidden compartment used to hide small weapons such as spikes, daggers or small amounts of poisons. Another use the sword had was that it could act as a small step by jamming the blade into the ground, the ninja could use the hand-guard as a step to get that extra height needed to scale a wall. It was common to have the tip of the scabbard come off so it could be used as a snorkel.