Wipe the kombu with a dry towel or paper towel.
Put all the ingredients in a pan and bring to a boil over high heat. Turn down the heat to low and simmer for 2 minutes to take the edge off the vinegar.
Cool, transfer to a container and keep in the refrigerator.
You can use this sauce in (Recipe ID: 1096848).
Or in (Recipe ID: 1118451)
Story Behind this Recipe
I use this sweetened vinegar in a lot in dishes, so I came up with this homemade alternative to my favorite brand.
Use white or usukuchi soy sauce. I guess everyone has their own favorite version of sweetened vinegar sauce. The 2 minutes specified in Step 2 is an approximate. Vary the amount of vinegar to taste.