Oni kenbai is an ancient folk art that has been handed down in the central and southern parts of Iwate Prefecture for generations. Its name translates to "Oni Sword Dance."

Dancers perform a fierce dance in white, red, blue, and black oni-like masks, whirling to the driving rhythms of drums, whistles, and bells. Then, having appeased any vengeful ghosts and evil spirits with their dance, the people pray for prosperity and good fortune. Though the masks themselves are demon-like, they actually represent a personification of the Buddha, which is why they have no horns.

Each mask color is said to have its own meaning. 

White mask: West, Autumn, the guardian deity of the West 
Red mask : South, Summer, the guardian deity of the South 
Blue mask: East, Spring, the guardian deity of the East
Black mask: North, Winter, the guardian deity of the North 

Oni kenbai masks are made with Narushima washi, a washi paper specific to Iwate Prefecture, which is also the northernmost washi tradition in all of Japan.