Morihiro Saito shihan stayed close to the founder Morihei Ueshiba, who taught him for 23 years. During that time, with his wife Sata san, he took care throughout day and night of Morihei Ueshiba and his wife, Hatsu. Morihiro Saito would always stay close to the founder to take care of the housework and rice fields, even after most students went away to avoid such demanding work. 

After the founder passed away, he became the first person in charge of the Ibaraki dojo. To help students better understand the weapon techniques, he organized and categorized hundreds of weapon and taijutsu techniques. He put all his passion into passing down everything learned from the Founder (Kaiso Jikiden). He was one of the few students who received weapon training from the founder and the only instructor who was allied to teach them at Aikikai Headquarters Dojo. Morihiro Saito shihan also devised the method to study the seven suburi movements, thirty-one jo kata, 13 jo kata, 20 jo movements. This study system also included the awase, kumitachi and parring weapon movements. 

He would also served as a high councillor of the Aikikai Foundation and contribute to the promotion of Aikido. 

In 1975, in California, USA, he held the first overseas seminar. After receiving a remarkable positive reception, overseas seminars were held every year. Subsequently, the Iwama dojo became a mecca for foreign Aikido artists; this particular training school would later become known as “Iwama Style”

He would continue his role as the guardian of the  Aiki Shrine throughout his life. In 2000, a video production named “Iwama Aikido” was produced to cover the costs to restore the Aiki Shrine. This video was highly praised by international martial arts practitioners worldwide.

This current land, where the Tanren-kan was built, was initially owned by the Ueshiba family and later handed over by second-generation Aikikai Doshu Ueshiba Kisshomaru.