American Yoshinkan Aiki Jujutsu was founded by Yutashi Hasaka. We are a traditionally-based aiki jujutsu system, meaning that while we place a strong emphasis on both solo and paired kata, freestyle randori as well as unconventional applications (boxing-type punching combinations vs shomenuchi, etc.) play a large role in our development. Let's explore the origins of our system, and then I'll describe what makes us unique among the vast number of aiki jujutsu ryuha.
In 1957, Yutashi sensei began modifying techniques and incorporating his own philosophies, laying the foundation for what would become American Yoshinkan. An in-depth striking repertoire was added from his Goju-Ryu Karatedo experience, as well as certain grounding principles more common of Okinawan Karatedo than Japanese Jujutsu. In the 1960s, Yutashi sensei first visited the United States and over the next thirty years would routinely travel back and forth before making a permanent home in California in the 1990s. It was then that Steven Hatfield began studying under Yutashi sensei who was a close friend of his father. Hatfield sensei remained a dedicated student until Yutashi sensei's death in 2007, when Hatfield sensei was named Soke*.
Going back to my opening statement, while it is difficult to offer a blanket analysis of the aiki principle, I feel obligated to describe how American Yoshinkan defines it. Aiki, translated as blending energy, is the systematic process of receiving the force of the attacker, processing it within our body and returning it while exerting little to no force of our own. Aiki is built around the concept that we all are comprised of energy, so by "blending energy" we refer to when our energies are connected through the point of contact. Rather than through muscular strength, the power of the techniques is derived from three sources: breath, the center line and cohesive movement. By using the body as a cohesive unit (not moving any part segregated from the rest of the body) and projection of the body through the core, power is generated without using any strength.
Below is a short clip of various American Yoshinkan techniques ranging from straight jujutsu to aiki jujutsu and pure aiki waza. Characteristic of our system are deep karate-like finishing stances when performing jujutsu locks and throws, as well as the explosiveness of our internals versus the subtlety preferred by other branches of aiki. Students learn jujutsu first, and only begin learning how to apply internal methods as they progress through yudansha ranks. Aiki no Jutsu is reserved for the highest levels, and it must be noted that any variation of aiki waza displayed publically is from the shoden and chuden levels (compared to the more refined variations of the okuden level).