Kenji Nakazawa was born in 1949 and brought up in Yokohama, Japan. He studied English and French in College and after graduating from Dokkyo University in 1972, worked for Kanagawa Prefectural Police Department.

In 1972 he joined the Kanagawa Prefectural Police Dept., stationed in Yokosuka. Whilst there, he studied various martial arts, training in Judo, Kendo and Taihojutsu. He experienced Judo and Taihojutsu competition for four years.

In 1976, he left Yokosuka for San Francisco,USA where worked for a tour company as a tour guide and interpreter for eight years. During his stay, he taught the self defense class at the sports clubs in Bay Area .

In 1984, he returned to Yokosuka, Japan and started working on the base in Yokosuka. There he met Amos Lee Parker Shihan and began his Yoshinkan Aikido training. He continued the training with him until Parker shihan returned home in 1990.  Prior to that he was awarded Yondan by Parker shihan.

In 1986, Parker shihan had introduced him to Terada Hanshi. He began attending to Hanshi’s Sunday morning  training class in Totsuka, Yokohama. Nakazawa Sensei enjoyed the training with Terada Hanshi until 2004. He was awarded Godan by Terada Hanshi. He accompanied his world tour to spread the Yoshinkan aikido in USA, Canada, Brazil, Australia, Russia and Ukraine.

In 2004, he stopped training in Yoshinkan Aikido and started his training in Shorinji Kempo, Eishinryu Iaido and Russian Sambo.

In 2008, he started developing his own style called, ”Aikisambo.” The name Ryuseikan was given to him for his new dojo. Since then he has conducted Aikisambo seminars and workshops in Russia, Ukraine, USA, Canada and South Africa.