An examination of Aikido's Fourth Teaching: an anatomical study of the tissues of the forearm

One of the basic teachings of Aikido is known as Yonkyo (Fourth Teaching) or Tekubi-Osae (Wrist Securing). According to some Aikido master teachers, Yonkyo is designed to attack the opponent's weak points. This investigation focused on examining this teaching with the purpose of describing the anatomical tissues involved in the etiology of pain when this teaching is applied precisely. Particular focus was placed on the anatomical locations/sources of pain associated with the application of this teaching.