Marinate water chestnuts in soy sauce for 30 minutes. Roll each chestnut in brown sugar, then wrap with a strip of bacon and secure with a cocktail pick or toothpick. Arrange on a cake rack in a shallow pan or in broiler. Bake in hot oven at 400° for 20 minutes. Drain on paper toweling. Before serving, return to a moderate oven at 350° for about 5 minutes to reheat and crisp the chestnuts. These are best when made in the morning and reheated. Makes about 16 appetizers.