Sushi roll with cucumber. かっぱ巻き。
Lightly pickled cucumber with sushi rice wrapped in nori seaweed. The long, thin sushi roll is cut into bite-sized pieces. With Tekkamaki (containing tuna) and Shinkomaki (containing Takuan), this is the most basic form of sushi roll.
The "kappa" is a mischievous creature from Japanese folklore living in ponds and streams and said to be fond of cucumber.
[Kappamaki. Photo Ad Blankestijn]