The name might suggest that there’s nothing to making this delicacy but soaking boiled eggs in soy sauce but there’s a little bit more to it than that.
First of all, “boiled” doesn’t necessarily mean hard-boiled. The eggs can be a little less cooked so that the yolks are still runny. The egg white, however, must be sufficiently cooked so that it is firm enough that when the egg is shelled, it doesn’t break and expose the soft yolk.
Second, the soy sauce in which the eggs are soaked isn’t soy sauce alone. A few other things are added. Rice wine and rice vinegar are not uncommon but other seasonings such as black pepper or chilies can be added too.
Third, the eggs don’t benefit from a really long soaking time. Leave them in the soy sauce mixture for too long and the eggs will turn out too salty. Fifteen minutes or so are enough to allow the eggs to acquire a good color and to absorb the flavors in the sauce.
If, however, you are not in a hurry to serve the eggs, you can soak them in the fridge overnight BUT you will have to dilute the soy sauce mixture with water. I did not want to do that because I wanted the soy sauce mixture to be usable forseasoning other dishes in the future.
Soy sauce eggs (shoyu tamago)

Ingredients
- ¼ cup light soy sauce I used Kikkoman
- 2 tablespoons mirin
- 2 tablespoons rice vinegar
- 4 boiled eggs
Instructions
- Mix together the soy sauce, mirin and rice vinegar in a bowl.
- Drop the shelled eggs into the mixture and leave for about 15 minutes. If the eggs are not completely submerged, use a teaspoon to roll them around every few minutes.
- Drain the eggs, cut into halves if you prefer and serve.