A kappa is a yōkai in Japanese folklore. The oldest writing about Kappa appears in a dictionary that was first made in 1444. It’s supposed to have a child-sized body and look like a frog or a turtle with a plate on its head. It lives in a river or a swamp and it likes wrestling with people who pass by. If you win against a kappa, then the kappa will always be compliant to you, but if the kappa wins, he may pull you under the water. It keeps water in the plate on its head, and it is said that it will die if the plate gets broken or dried out. The kappa is said to be especially fond of cucumbers, so the sushi roll with cucumber is known as a Kappa Roll because of this fact.
