The traditional Obon event of Oohasama, the Andon Festival, has a history of about 200 years and is said to have begun as a memorial service for those who starved to death during the great famines of Tenmei (1781-88) and Tenpo (1830-43) during the Edo period. It is said that it first began when a monk from Oohasama and young believers pulled around a lantern in their hands as a memorial service for the hungry ghosts, and that it began to be carried around in its current form on a large eight-cart around the Meiji period.

In the past, the floats were paraded for three days on August 14th, 15th, and 16th, with a different performance each day, but now the festival is held for two days, the 14th and 16th, with a day off in between. The performances include pictures of warriors and Kabuki themes, as well as Buddhist paintings for ancestral worship, and the four floats are paraded through the towns, mainly by young people from each district.
It is currently designated as an intangible folk cultural property of Hanamaki City (March 25, 2005).