Vintage Windmill Sunset Mug/The Otagiri Mercantile Company tea coffee cup

Vintage OMC Japan Mug It is missing the sticker label on the bottom. This cup is so cute and vibrant. The design is textured a bit, but I’m not 100% if it’s hand painted. It’s in good condition, however there is a smooth tiny knick near the top of one side (see picture). There are imperfections in the actual make of the cup itself.