With the heat off, combine the grated ginger, ground chicken, sake, mirin, sugar, and soy sauce in a medium saucepan.

Turn the heat to medium-low. Using 3 pairs of cooking chopsticks, stir constantly, breaking the meat into fine crumbles for 3-4 minutes. Continue cooking until most liquid has evaporated and the chicken is glossy and glazed, about 2-3 more minutes. Set aside.

In a separate cold saucepan, combine the eggs, 1 tablespoon sugar, and salt. Beat with chopsticks until the sugar is dissolved.

Turn the heat to medium-low and cook the egg mixture, stirring constantly with chopsticks, scraping from the bottom and sides. Break up large curds and cook until just set but still moist. Remove from heat immediately.

Divide the cooked rice between two donburi bowls. Spoon the ground chicken over one half of the rice and the scrambled eggs on the other half. Arrange the green peas in a line down the middle.

Garnish with pickled red ginger if desired and serve.