John Dempsey Jr. is a martial artist, Shiatsu Therapist, and a Fitness Instructor Specialist. He began his martial studies in boxing at the age of 16, and soon moved on to Kempo. From there he pursued Budo/Ninpo Taijutsu, and later on, Goshin-jitsu. In 2001 he earned his Shodan in Goshin-jitsu, and in 2002 his Nidan, at which time John began formally teaching on his own. After spending 15 years competing in tournament circuits, John gave up competition to become more of a traditional martial artist. John had always found human anatomy fascinating, and he believes strongly that a good martial artist has expert knowledge of anatomy, (including weaknesses), and physiology. This belief has been reflected in his studies over the years in college/university courses in anatomy/physiology/pathology, and in his studies in reflexology, shiatsu, and Eastern meridian/medical theory. His focus has always been on private instruction. He prefers to teach this way, as it lets him focus on one person at a time for maximum results.

John graduated with honours from the Shiatsu Therapy program, at the Shiatsu School of Canada in 2013. It is here that he learned what he calls, 'the missing pieces', to his martial studies, particularly in Eastern meridian and tsubo theory, Qi-gong, nutrition, and Eastern medical theory. These missing pieces gave him a deeper understanding of the concepts of the Five Animals of Kempo/Kung-fu, and helped him to re-invent and expand the style of Goshin-jitsu by adding in Chinese components from Shaolin/Okinawan Kempo, Qi-gong, meridian theory, pressure/healing points, and Eastern medical theory. Whereas this style used to be a mix of only Karate/Judo/Jiu-jitsu, John's version, which he calls 'Gogyo Goshin-jitsu', is a mix of Karate/Judo/Jiu-jitsu/Kempo/Qi-gong.  As mentioned, John is also a Shiatsu Therapist, and operates a small home clinic, in the same location as Ryuuko Dojo.