Introduction: Purpose and Policy

The purpose of this book is to scientifically examine the techniques of Aikido or Aiki-Jujutsu. Throughout Japan’s long history, many fighting techniques were developed and refined by our predecessors [1, 2]. Aikido or Aiki-Jujutsu (hereafter referred to as Aikido) is believed to have evolved as masters of each era created new techniques from those inherited from the past. Today, Aikido is practiced not only in Japan but also all around the world. Numerous books on Aikido have been published [3–9], and Aikido dojos are now commonly found in large cities. Aikido attracts many people for various reasons. It is often understood as a self-defense technique. Indeed, as a martial art, it can be used to subdue an opponent and protect one’s life or the lives of others from an attack. However, the appeal of Aikido lies not in advanced killing techniques.