Cut the chicken into 5cm pieces. Combine the chicken with the soy sauce, sake, ginger juice and sugar and stand for 10 minutes.

Place the flour in a tray or large bowl. Pull the chicken out of the marinade with chopsticks and drop it into the flour, one piece at a time. Adding the pieces one at a time stops you from pouring in too much of the marinade, and stops the chicken from sticking together. Shake any excess flour from the chicken and place in a tray in a single layer. Allow the floured chicken to stand, uncovered for at least 5 minutes before frying.

Heat the oil to 180°C in a wide saucepan. Add the chicken to the oil in batches. For each batch, deep fry for 1 minute then remove the chicken to a rack and rest for 30 seconds. Return the chicken back to the oil and fry for 30 seconds, and then rest on a rack again for 30 seconds. Transfer the chicken back into the oil for one last blast of 30 seconds to a minute, and then rest for a two minutes on a wire rack.

Serve the chicken with a lemon wedge, and a little Japanese mayonnaise scattered with shichimi togarashi (if using).