Combine the ingredients: Add ketchup, Worcestershire sauce, soy sauce, granulated sugar, and Tabasco sauce to a small saucepan.
Whisk until smooth: Stir everything together until the sugar is evenly distributed and the mixture looks smooth.
Warm gently: Place the saucepan over low to medium-low heat and cook for about 5 minutes, stirring occasionally.
Avoid a hard boil: Keep the heat gentle rather than aggressively boiling the sauce. The goal is to bring the flavors together without reducing it too far.
Check the consistency: Dip a spoon into the sauce. It should coat the spoon lightly and still pour easily.
Taste and adjust: Add a little more Tabasco for heat or a small splash of Worcestershire sauce for extra tang if needed.
Cool before serving: Remove the sauce from the heat and let it cool for several minutes. It will become slightly thicker as it cools.
Serve with chicken: Spoon or dip the sauce with crispy chicken katsu, or serve it alongside rice, fries, sandwiches, or grilled chicken.