In the late thirties, the Japanese army was heavily involved in the war. Most young students of Morihei Ueshiba were conscripted into the army. This conscription reduced the ranks in the Kobukan dojo , which involved a reduction of the activity in the dojo when the Pacific War began. In 1942, after falling ill following a severe intestinal condition, Master Ueshiba decided to establish a new basis for the organization of Aikido in Ibaragi Prefecture, in the village of Iwama where he purchased some land a few years ago. He then left the charge of the dojos in Wakamatsu -cho to his son Kisshomaru Ueshiba. In Iwama , Morihei began the construction of what he called the Ubuya ( birthplace) , the sacred circle of Aikido : An assembly comprising the altar of aiki with a dojo outside. This was completed in 1964 by a group of beautiful sculptures:Forty-three guardian deities of Aikido. The dojo, now known as the Ibaragi Dojo, was completed in 1945 just before the end of the war. There, far away from the bustle which reigned in Tokyo because of the war, he invested in agriculture , training and meditation.

These years in Iwama proved decisive for the development of modern aikido. Morihei , with an utmost concentration involved himself in intensive training in order to perfect his martial art dedicated to the peaceful resolution of conflicts.

At the end of the war, the founder had few students in Iwama, the prewar disciples being dispersed throughout Southeast Asia .

It was at this time, during the summer of 1946 , that a young man employed at the Japanese Société Nationale des Chemins de Fer, enrolled at Iwama dojo . Morihiro Saito became one of the closest students of the founder and later his technological successor.

It was at this time that the founder detailed study of the sword called in Aikido ‘Aiki Ken’ and the study of the stick : Aiki Jo . He considered that it was essential to know the handling of these weapons to execute techniques properly with bare hands.

He then prepared a complete Aikido program including weapons practice and practice with bare hands. It was also at this time that the young Saito was used mostly as training partner for Master Ueshiba, which enabled him to discover many techniques that the founder taught very rarely. During this part of his past life in Iwama , Ueshiba defined the concept of TAKEMUSU AÏKI , which corresponds to the spontaneous execution of an infinite number of suitable techniques on attacks whatsoever. During the fifties Ueshiba traveled extensively throughout Japan to meet countless requests addressed to him. He also spent a few days a month in Tokyo before going back to Iwama. It was, at that time, very difficult to predict from one day to another, where Master Ueshiba was and even to know when they would cease to run a course at the Aikikai Tokyo. Many students, who began training after the war and had the opportunity to see the founder teach or conduct demonstrations, were excited by the energy and beauty of his movements, as well as by his ethics of martial arts. At that time his technique flowed like a river of his mind, without limitation, fundamentally different from the extremely harsh practice that highlighted the physical strength that characterized his early years. During the last years of his life, when his health began to deteriorate, Ueshiba moved slower and less freely, so he adopted his techniques in shortening them. He projected his students with a quick gesture or a small hand movement and sometimes without touching them. This part of his life coincided with the beginnings of the international development of aikido by public demonstrations and dissemination of films that are causing many imitators who did not understand that this aikido , was a natural result of past experiences and the results of more than sixty years of practice, not a beginning. Morihei Ueshiba died of liver cancer on 26 April 1969. He received the same day his last posthumously distinction from Emperor Hirohito . His ashes rest in the temple of the Ueshiba family atTanabe and strands of his hair are preserved as relics on the altar of the Iwama Aiki, at the family cemetery Ayabe and at the high altar Kumeno . Kisshomaru his son succeeded him as the second Doshu of Aikido.