Cut the Chicken
Slice chicken into 2-inch bite-sized pieces for even cooking.
Marinate
In a bowl or ziplock bag, mix soy sauce, sake, ginger, garlic, sugar, and mirin.
Add chicken, massage the marinade in, seal, and refrigerate for 30 minutes to overnight.
Prepare the Coating
In a clean bowl, combine cornstarch and plain flour.
Coat the Chicken
Pat each chicken piece dry with a paper towel.
Dredge in the flour-starch mixture until fully coated.
Heat the Oil
Pour oil into a deep pan.
Heat to 170–180°C (340–355°F). Use a thermometer or test with a chopstick—bubbles should form rapidly.
First Fry
Fry chicken in batches for 3–4 minutes until light golden.
Drain on a wire rack or paper towel. Let oil reheat between batches.
Second Fry (Double-Frying Method)
After 5–7 minutes of resting, fry chicken again at 190°C (375°F) for 30–60 seconds until crispy.
Drain again on a wire rack.
Serve
Plate with shredded cabbage, lemon wedges, and optionally, steamed rice and miso soup.