Yakitori Sauce is a Japanese sauce for barbequing.
Items are brushed with it before grilling, then brushed with it a few times more while cooking. The sauce is also served at the table as a dipping sauce.
There are many different versions: some will add fish stock, others chicken stock.
Yakitori Sauce can be bought in bottles at stores. Some brands are even aged for up to 3 years.
2/3 cup (6 oz / 175 ml) soy sauce (dark)
2 tbsp mirin
2 tbsp sugar
Combine, bring to a boil, let boil for 30 seconds. Remove from heat, let cool.
If you plan to use the sauce as a dipping sauce at the table, set that sauce aside first so that you don't contaminate it with any raw meat juices from the brush.