Stier Sensei began training in 1973 with the UMass Aikido Club in Amherst MA under the direction of Dr. Taitetsu Unno Sensei, a student of Akira Tohei Sensei. During his time with UMass Aikido he met his eventual teachers, Paul Sylvain Shihan and Lorraine DiAnne Shihan. Sylvain Sensei and DiAnne Sensei were his sempai and they encouraged him to join them on many trips to Kenmore Square to train with Mitsunari Kanai Shihan at New England Aikikai. Stier continued training with Kanai Sensei during the summers of his undergraduate career.
In 1976, Sylvain and DiAnne Sensei left to train at Hombu Dojo and became special apprentices to T. K. Chiba Sensei. Upon their return in 1979, they asked Stier Sensei to help them build their new dojo, Amherst Aikikai. Stier received his Shodan in Aikido in 1981 and, shortly after that, his Shodan in Iaido. He remained affiliated with USAF Eastern Region with Kanai Sensei and Yamada Sensei, although a special relationship with Chiba Sensei would play an important role in his Aikido development.
In 1986, Stier helped open Valley Aikido in Northampton, MA with Sylvain Sensei. At Valley Aikido, he became Sylvain Sensei’s first student to be given a regular class. Soon thereafter, in an effort to grow our student base, Sylvain Sensei sent him out to teach weekly classes with students in Brattleboro, VT and Greenfield, MA. Those efforts continued until the untimely death of Sylvain Sensei in 1996. Stier assumed a greater role at Valley Aikido as co-head instructor and continued in that role for nearly 10 years. He opened Green River Aikido with his wife Kathy in 2005, and was promoted to the rank of nanadan in 2024. Stier felt the need to more thoroughly explore the weapons aspect of his training in order for his Aikido to evolve so he was naturally attracted to Chiba Sensei’s teaching and use of weapons in his training. In 2011, Chiba Sensei officially accepted Stier Sensei as his student and Green River Aikido as active members of Birankai North America.