Boil the mirin and sake in a wok or frying pan.
Pour in the soy sauce.
Stir in the sugar.
Scatter the chicken thigh fillet slices in the boiling liquid and allow the liquid to reach boiling point once more. Lower the heat to medium and let the chicken cook for 5 to 6 minutes.
Scatter the trimmed snow peas over the chicken. Cook for one minute.
Pour the eggs over the chicken and snow peas in a circular motion. When the edges look firm, turn off the heat and let the eggs continue cooking in the residual heat.
Scoop the chicken, eggs and snow peas over hot rice. Drizzle in some sauce. Serve the chicken, scrambled eggs and snow peas rice bowl at once.