Abstract
Sweet potato has been eaten by itself as a substitute for the staple food or mixed with rice in such dishes as imomeshi (cooked rice with sweet potato) and imogayu (rice gruel with sweet potato). We investigated the areas where these dishes have been eaten during the Taisho, Showa and Heisei eras, and related this consumption to the transfiguration and characteristics of each era and area. The results show that the area for eating imomeshi has been spreading from the western to eastern part of Japan during the passing of these eras, while eating imogayu has remained in western Japan. It seems that the spreading popularity of sweet potato was responsible for wider geographical area and familiarization of eating imomeshi. It also seems likely that the different image and eating habits of rice gruel between western and eastern Japan influenced the localization of eating imogayu to western Japan.
