This is an extremely popular legend among the Japanese. Benkei is on a pilgrimage to the Tenjin shrine at Gojo (5th Avenue) bridge. His attendant advises him not to go because it would be dangerous. Benkei encounters a fleeing crowd running from the bridge. Just then Ushiwakamaru appears; he has vowed to take 1,000 swords to appease his father's spirit. One after another he fells the fleeing people. Benkei thinks Ushiwakamaru is being childish. When they meet, they duel and Benkei loses. He becomes Ushiwakamaru's retainer and they depart.

A synopsis of the Noh Play can be found here.