Aikido is a modern Japanese martial art that is split into many different styles, including Iwama Ryu, Iwama Shin Shin Aiki Shuren Kai, Shodokan Aikido, Yoshinkan, Renshinkai, Aikikai and Ki Aikido. Aikido is now practiced in around 140 countries. It was originally developed by Morihei Ueshiba, as a synthesis of his martial studies, philosophy and religious beliefs. Ueshiba's goal was to create an art that practitioners could use to defend themselves while also protecting their attackers from injury. Aikido is often translated as "the way of unifying (with) life energy" or as "the way of harmonious spirit". According to the founder's philosophy, the primary goal in the practice of aikido is to overcome oneself instead of cultivating violence or aggressiveness. Morihei Ueshiba used the phrase masakatsu agatsu katsuhayabi" to refer to this principle.

A tantō is one of the traditionally made Japanese swords that were worn by the samurai class of feudal Japan. The tantō dates to the Heian period, when it was mainly used as a weapon but evolved in design over the years to become more ornate. Tantō were used in traditional martial arts. The term has seen a resurgence in the West since the 1980s as a point style of modern tactical knives, designed for piercing or stabbing.