Add water, ginger, soy sauce, vinegar and salt to a small pot, heat on medium heat till bring a boil. Turn to low heat and boil for 8 minutes. Remove pot from stove to chill down.

After the mix liquid in the pot is cool enough, add eggs and the liquid in a small container. Let the liquid to cover the eggs. Marinate in the fridge overnight. The eggs could be stored in the fridge for 2 days.