01 - Bring a pot of water to a rolling boil.
02 - Gently lower the eggs into the boiling water using a spoon. Boil for exactly 7 minutes for slightly runny yolks.
03 - Prepare an ice bath. Immediately transfer the cooked eggs to the ice bath and let cool for 5 minutes.
04 - Carefully peel the cooled eggs, removing all shell fragments.
05 - In a zip-top bag or small container, combine soy sauce, water, mirin, and sugar. Mix until the sugar completely dissolves.
06 - Place the peeled eggs in the marinade, ensuring they are fully submerged. Marinate in the refrigerator for at least 4 hours, preferably overnight, turning occasionally for even color.
07 - Remove eggs from the marinade, slice in half, and serve atop ramen or enjoy as a flavorful snack.