In a medium saucepan, combine soy sauce, mirin, water, dried kelp, and sugar. Heat over medium-high and bring to a gentle boil. Once bubbling, reduce heat and simmer for 2 minutes until sugar dissolves. Allow the marinade to cool completely.

Carefully crack the eggs and separate the yolks from the whites. Place yolks in a shallow glass container in a single layer.

Once the marinade has cooled, strain it through a fine-mesh sieve to remove the dried kelp. Pour the strained marinade over the yolks, ensuring they are fully submerged. Seal the container.

Transfer the sealed container to the refrigerator and let the yolks cure for at least 12 hours, up to 48 hours. Gently flip the yolks every 12 hours for even exposure.

Once cured, remove the yolks with a slotted spoon. Serve on warm rice, drizzled with sesame oil, and garnished with chopped scallions and crushed nori.