Mix the soy sauce, mirin, sake, sugar and ginger in a small bowl. This is the teriyaki sauce.

Heat the oil in a frying pan over medium high heat. Fry the chicken, skin side down first if using skin on, for 5 to 6 minutes until browned.

Turn and cook for a further 4 to 5 minutes until cooked through.

Pour in the teriyaki sauce and simmer for 2 to 3 minutes, turning the chicken to coat, until glossy and slightly thickened.

Slice the chicken and serve over rice with any extra sauce spooned over, scattered with spring onion and sesame seeds.