Slice the chicken breasts into 1cm strips and set aside.
In a bowl whisk sake, mirin, soy, sugar, garlic and ginger. Add the chicken, cover and leave in the fridge for at least 4 hours, but preferably overnight.
In a sturdy blender or food processor blitz the broken up ramen until you get a fine, flour like powder. Set this aside.
Heat the oil to around 170°F/340°F.
While waiting for the oil to heat up dredge the marinated chicken in the ramen flour, making sure it's really stuck on. Dip the coated chicken back in the marinade and then again in the flour to get an extra thick crust.
Fry in small batches for roughly 2 - 3 minutes until dark and crisp, draining each batch on some kitchen towel.