This is possibly the easiest marinade ever, save for opening a bottle. We used it last night to add colour and flavour to slices of firm tofu, before grilling them on a hot stovetop grill. It’s somewhere between a teriyaki and a yakitori and also works well on fish, pork, chicken and veggies. (I would suggest using it on thinner cuts of meat, though, as the sugar content in the Mirin could cause it to burn if cooked for a longer time.)
Combine equal parts Mirin and Tamari (or soy sauce).
Optional: if you have an extra minute, add a little fresh minced garlic and ginger.