Aiki Jinja (合気神社) is the shrine built by Morihei Ueshiba in Iwama in honor of the deities of aikido. (Jinja is the Japanese term for a shrine.) The shrine grounds include the Ibaraki Branch dojo (training hall).
The first part of the shrine building (the Honden, housing the dieties of aikido) was built in the 1940s. The second bigger part (the Haiden) was erected in front of the Honden in 1962. Both parts were renovated by the Saito family in 2001-2002 with the approval of Dōshu Moriteru Ueshiba. This renovation also included a fence set up around the compound, and a huge stone with the carvings "Aiki Jinja" designed by Seiseki Abe, a master of both calligraphy and Aikido who was the calligraphy teacher of Morihei Ueshiba.
Once a month, Ueshiba would preside over what was initially a very small religious ceremony in the aiki jinja called Tsukinamisai (月並み祭), which lasted up to an hour. Food offerings of fruits, vegetables, and fish - but no red meat - adorned the shrine. Eventually, the Saito family took responsibility for hosting the ceremony every month on the 14th. Later, a small party with all the uchi deshi (resident students) and the Saito family was held inside the old dojo. This tradition is kept up by current Dōshu Moriteru Ueshiba.
Every year on April 29 (the start of the Japanese Golden Week holiday), the annual shrine festival is held by Oomoto priests in commemoration of Ueshiba's death on April 26, 1969. Through the years, the Saito family developed this event, transforming it into a very big day for the small town of Iwama. Hundreds of Aikido practitioners come to Iwama to participate in the event. A religious celebration is held inside the shrine and ancient music is played. Before finishing, a small ritual demonstration of Aikido, hōnō embu (奉納演武) is held. To finish, all of the visitors are invited to a huge lunch in the dojo compounds.
Read more about this topic: Iwama Dojo