Make the marinade. In a small bowl, combine soy sauce, water, mirin, sugar, and rice vinegar. Stir until the sugar dissolves. Add ginger and garlic if using. Taste and adjust the sweetness or saltiness to your liking.

Prep an ice bath. Fill a medium bowl with cold water and plenty of ice. You’ll use this to stop the cooking and keep the yolks jammy.

Bring water to a boil. Fill a medium pot with enough water to cover the eggs by about an inch. Bring it to a rolling boil over medium-high heat.

Lower the eggs in gently. Use a slotted spoon to carefully lower cold eggs into the boiling water. Reduce heat slightly to maintain a brisk simmer, not a violent boil.

Set your timer. For jammy yolks, cook for 6 minutes and 30 seconds to 7 minutes. If you like them a bit firmer, go up to 7 minutes and 30 seconds. Keep the water moving gently for even cooking.

Shock immediately. When the timer goes off, transfer eggs straight into the ice bath. Let them chill for 10–12 minutes so the centers set and peeling gets easier.

Peel with care. Tap each egg all over to crack, then peel under running water. Start at the wider end where the air pocket is; the shell usually lifts more cleanly there.

Marinate. Place peeled eggs in a zip-top bag or snug container. Pour in the marinade so the eggs are fully covered. If using a bag, gently press out excess air so the liquid hugs the eggs.

Chill and wait. Marinate in the fridge for at least 4 hours, ideally 8–12 hours. For deeper flavor and color, you can go up to 24 hours, but not much longer or they may get too salty.

Serve. Slice in half and serve over ramen, rice bowls, salads, or toast. Spoon a bit of marinade over noodles or steamed vegetables for extra flavor.