Cut the chicken into 5cm pieces.
Combine the chicken with the soy sauce, sake, ginger juice, and sugar. Let it stand for 10 minutes.
Place the flour in a tray or large bowl. Coat the chicken pieces in flour and let them stand for at least 5 minutes before frying.
Heat the oil to 180°C. Deep fry the chicken in batches, with rests in between, until crispy and cooked through.
Serve the fried chicken with lemon wedges, Japanese mayonnaise, and shichimi togarashi.