Ninja (忍者) or shinobi (忍び), agents or mercenaries in feudal Japan. Espionage, sabotage, infiltration, assassination and in some cases open combat are the main tasks of ninjas. These people, who lived a secret life at the foot of the mountains, mostly banished from the presence of their masters or left of their own accord, took their place in history as ninjas, a secrecy-based martial art created by samurai to turn their being outnumbered into an advantage over time. A ninja should have mastered many fighting and mental techniques. These qualities were usually necessary to defeat the well-trained samurai they were dealing with as their opponents. These techniques of ninjas formed a separate fighting branch over time and got the name Ninjutsu. Because it was necessary to know how to use even a stick in such a way that it could seriously injure or even kill the opponent in necessary situations.

In addition to weapons such as the classic katana and the bow, developing weapons that can provide a great advantage against many other weapons was one of the priority tasks of the ninjas. In addition to fighting, these weapons were designed to greatly help with the work required for stealth, such as climbing a tree, digging.

Over time, the fighting technique used by ninjas became known as Ninjutsu. The Japanese began to spread this deadly warfare technique after the 1980s and it took its current form. Before that, it was only passed down from generation to generation.