We investigated what variety of blue used in patterns on Sometsuke plates most increases one's appetite. We adopted the color designated 2.0 PB 4.2/6.7 in the Munsell color system (HV/C) as our standard blue color, 1.4 PB 5.0/6.7 as blue-green, and 7.1 PB 3.6/4.8 as a low-chroma color. The plates were baked with the same design but in the 3 different colors mentioned above. A solid white plate was added. Twenty items frequently served in industrial cafeterias, hospitals, nursing homes, and the like were shown to subjects on these plates, and then a questionnaire survey was conducted about changes in their appetite. All of the blue-patterned plates increased the subjects' appetite more than the white plate did. While there were some items that matched well with the blue-green or the low-chroma color, no significant differences from the standard color were found in rating or rank. Therefore, among the three colors, the standard color of blue was found to be most effective in increasing one's appetite.