Select the color you want and click on a prefecture on the map. Right-click on it to remove its color, hide it, and more. Advanced...
Add the title you want for the map's legend and choose a label for each color group. Change the color for all prefectures in a group by clicking on it.
Drag the legend on the map to set its position or resize it. Use legend options to customize its color, font, and more.
Select layout for the user interface:
Simple - Reversed ⚡
Your selection will be saved for your next visits to this map page. You can always change this back.