In a saucepan combine the soy sauce, the mirin, the vinegar, the sugar, the gingerroot, and the beer, simmer the mixture until it is reduced to about 1 1/3 cups, and let the marinade cool until it is room temperature. In a shallow baking dish large enough to hold the pork chops in one layer combine the pork chops and the marinade, turning the chops to coat them thoroughly, and let the chops marinate, covered and chilled, turning them several times, overnight.

Pour the marinade into a saucepan and boil it for 5 minutes. Grill the pork chops on an oiled rack set about 4 inches over glowing coals, basting them with the marinade during the last 5 minutes of the cooking time, for 8 minutes on each side, or until they are just cooked through. Alternatively the pork chops may be broiled on the rack of a broiler pan under a preheated broiler in the same manner.

Servers 6