Japan's municipal merger policy in the 2000s created many merged municipalities without a core area, which seems to have produced more local development problems than in other municipalities. To determine their local development strategies, how they establish and use new local images in their development policies is examined. The focus is on Hokuto City in Yamanashi Prefecture as a case of merged municipalities without a core area. Hokuto City developed from a municipal merger that excluded the regional core, Nirasaki City. The jurisdiction of Hokuto City is divided by cliffs into three areas, which are represented respectively by mountains. It is difficult for the Hokuto City administration to use an image of one of these areas for fear of objections by the other areas. Therefore, it requires new images for the developmental policies of the Hokuto jurisdiction. The city administration is attempting to communicate “sunshine” as the image of Hokuto City. This was once the image of Akeno-mura, a former municipality that later became part of Hokuto, where the longest period of sunshine in Japan was recorded. The image has contributed to attracting mega solar energy systems to a national research project in Hokuto. Following the research, these solar energy systems will be owned by the Hokuto City administration and will support the city's finances by selling the electricity generated. This can be interpreted as a case of the city administration scale jumping the image of “sunshine” from Akeno to Hokuto. This scale-jumped image contributed to attracting the mega solar energy systems; then, the presence of the solar energy systems improved the plausibility of the scale-jumped image. Such scale jumping of images seems to be effective in the local development policies of merged municipalities.