Flavor Step - In a heavy pot just large enough to hold the pork, bring the sauce ingredients to a boil. Add the pork; the liquid should come halfway up the side. Add more liquid if needed. Reduce the heat to a simmer and cover the pot. Simmer for 15 minutes, turn the loin over, and simmer, covered, for 15 minutes more.
Turn off the heat and let the pork sit for 2 to 3 hours in the covered pot to cook slowly as the meat and stock come to room temperature. Turn the meat over from time to time.
Slice the pork. You can brush the slices with sesame oil and sprinkle on some sesame seeds if you wish. Serve the meat at room temperature or slightly warm, reheated in the sauce.
Note: To save the Master Sauce, strain it and discard the solids. Store in a covered container in the refrigerator for 5 to 7 days or freeze it. To use, add more stock or water and seasonings as needed and follow the cooking directions.