Add the sake, soy sauce sugar and grated ginger to a frying pan and whisk to combine. Add the chicken and use a spatula to break up the chicken and mix with the marinade. The chicken should have the consistency of loose oatmeal. Let this marinate while you prepare the eggs.
For the eggs: Beat the eggs, salt and sugar together until it is a uniform color.
For the chicken: Put the chicken on the stove over low heat and slowly cook while breaking up any chunks that form with a spatula. As the chicken cooks, a lot of liquid will come out and at one point it will look almost soupy. This is fine.
Once the chicken is cooked through turn up the heat to high and boil off all the liquid. Once the liquid has evaporated, the chicken should start frying in its own fat. If your chicken was very lean you may need to add a teaspoon of oil. Let the chicken fry until the chicken browns and the sauce has caramelized.
When the chicken is done, pour the eggs into a non-stick pan and then turn the stove on to medium low. Once the eggs starts to set in the middle, use a whisk or chopsticks to vigorously scramble the eggs to make small grains of egg about the size of the chicken.
To assemble: Cover half the rice with the egg and the other half with the chicken. Garnish with scallions and serve with your favorite hot sauce.