Oishida is called rainbow town because it usually has shower so rainbow often appears on Oishida's sky. Famous poet Mokichi Saito had stayed here for 2 years, then he made a poem. A sentence on it is "piece of rainbow has left on the sky" is Japan-wide phrase. That's why there are many buildings named "rainbow 〜〜〜” such as rainbow plaza, rainbow hotel. Though we don't have any rainbow color at all in the town. I decided to increase rainbow color stuff here.