I have a recipe which calls for mirin but r/o
Are there brand names for the mirin? In my Japanese kitchen I have a "cult" mirin and it reads that the alcohol percentage is between 13.5 and 14% alcohol.
When I lived in the north woods of Minnesota and had no access to mirin, I used sake and sugar. Not the same results (of course) but an acceptable alternative.
Up your sake and add sugar to taste. If I could do this in Dent, Minnesota, you could do this ANYWHERE on the planet!