2.5 cups (425 g) uncooked short-grain rice (Nishiki is my brand of choice)
5 oz (150 g) boned chicken
1/2 medium onion
2 scallions (green/spring onion)
6 eggs, lightly beaten
1 2/3 cups (400 mL) bonito stock (dashi)
7 Tbsp soy sauce
2 Tbsp mirin
2 Tbsp sugar
Cook rice as you normally would (I prefer my National fuzzy-logic rice cooker). Cut the chicken into 1/2 inch cubes, drop into boiling water just until the colour changes, then transfer to cold water and drain. Slice the onion thinly, cut the scallions diagonally diagonally into thin rounds. Combine all the sauce ingredients in a saucepan and boil over high heat, stirring constantly, until the sugar is dissolved.
Make 1 serving at a time, transfer 1/4 of the sauce into a small clean saucepan, add 1/4 of the chicken and onion, and place over high heat. When the chicken is done, add the scallion, then pour in 1/4 of the lightly beaten egg in a broad circular motion to cover as much suface area as possible. When the outer edges of the egg begin to set, stir through once in an X motion with chopsticks or fork. Fill a deep soup bowl with 1/4 of the cooked rice, and when the egg is soft set, slide the chicken-egg-onion mixture in its sauce onto the rice. Cover and make the remaining three servings.
I have been known to lazily cook the chicken in the sauce, skipping the first cooking, and also to make all four servings at once.