Aikijutsu is an ancient Japanese martial art used by the buke (the warrior class of feudal Japan) as a system of the application of armed and unarmed combat techniques.
Aikijutsu (aka Aiki Jujutitsu) is based on the principle of yielding rather than withstanding an attack. By utilizing an attacker’s energy against them, through the use of biomechanical forces, an Aikijutsu practitioner can effectively control and dispatch an attack. This is so even against larger or multiple opponents. The practitioner seeks to become an amplifying mirror of his/her opponent; the more aggressive the attack, the more devastating the defense. Aikijutsu contains many defensive techniques that incorporate striking, pressure-points, joint-locks, throws, and chokes.
Aikijutsu, is actually the unarmed subset of a larger system of warfare known as Aiki Bujutsu, which also includes the application of the above principles to weapons and tactics of combat. Aiki principles have spilled over into such other relatively new martial arts such as: Aikido, Judo, Hapkido, and countless others. Aikijutsu was prominent among the buke of Japan and may have actually eclipsed its close “cousin” Jujitsu at time, especially among certain clans of samurai.
There are many different styles or ryu of Aikijutsu. Some preserve the ancient methods of techniques (e.g., Takedaryu, Daitoryu), while others emphasize modern application and modification (e.g., Shindoryu). All keep the major concept of yielding and harmonizing rather than clashing in their techniques. Note that the practitioners within these different camps of Aikijutsu may be quite contentious.