1.Place eggs in small pot of water, covering the eggs. Turn burner to medium and cook eggs for 6 minutes (soft boiled) or 10 minutes (hard boiled). Place eggs under running water to cool and then peel.
2.Combine the water, sake, soy sauce, mirin, and sugar in pot and bring to a boil. Boil for 5 minutes until the sugar is dissolved.
3.Place peeled eggs in a small container that fits all the eggs snugly. Pour liquid over eggs. Cover container and let marinate in the refrigerator for one day.
4.Take eggs out of the fridge one hour prior to serving to take the chill off or you may heat up the eggs and liquid together in a pot for a few minutes.