01 - Prepare all ingredients. If you haven't cooked the rice yet, start that first.
02 - In a large, deep skillet or donabe (Japanese clay pot), combine dashi, soy sauce, mirin, sake, and sugar. Stir and bring to a gentle simmer over medium heat.
03 - Add the sliced onions and cook until softened, about 3 minutes.
04 - Layer chicken pieces over the onions. Cover, and simmer for 6–8 minutes, until chicken is cooked through.
05 - Pour the beaten eggs evenly over the chicken and onions. Cover again and cook for 1–2 minutes, until the eggs are softly set but still slightly runny.
06 - To serve, spoon hot rice into bowls. Gently slide portions of the chicken, egg, and sauce over the rice.
07 - Garnish each bowl with sliced spring onions. Serve immediately.