Ricardo Diaz Sensei began his martial arts training in Tae Kwon Do at the age of eight and he continued training until he was 15 years old. While in college he trained intermittently. After completing medical school he met Sensei Lonnie Schwartz, a podiatrist at St. Paul Medical Center. Sensei Schwartz invited Ricardo to train in Shorin-Ryu with the Beikoku Shidokan system under Hanshi 10th dan|Seikichi Iha. He trained from 2003 to 2013 and achieved the rank of 1st Kyu. While training under Sensei Schwartz, Ricardo met Sensei Sean Deuby. Sensei Deuby had prior training with Hanshi Iha and eventually became co-founder of OKCD.
In 2014, Ricardo began attending classes at OKCD. He was impressed with the curriculum of the dojo and the commitment of the instructors and he officially joined the dojo in October 2015. Ricardo was awarded the rank of Shodan in January 2019 and his Nidan in December 2020. In addition to his participation in the dojo, Ricardo has a private practice in Internal Medicine and enjoys activities with his six grandchildren.