Add the rest of the ingredients and mix well. If your ketchup, etc. are refrigerated, it may cause the butter to solidify and your sauce to turn grainy. If this happens, you can pop it in the microwave for a few seconds to smooth it out.
1/4 cup ketchup, 1 Tablespoon worcestershire sauce, 1 t soy sauce, pinch garlic powder
Serve with tonkatsu, chicken katsu, korokke, or even dip your fries in it!