1 1/4 pounds boneless chicken thighs, cut into about 1-inch pieces
3 tablespoons soy sauce
2 tablespoons sake
1 tablespoon mirin
2 teaspoons ginger juice
1 cup potato starch, or cornstarch, or as needed for coating
1/2 cup vegetable oil, or the amount needed for deep-frying
Mix soy sauce, sake, mirin and ginger juice in a large bowl.
Marinate chicken in the sauce for 30 to 60 minutes.
Take out the chicken from the sauce and dry lightly with paper towels.
Preheat oil to about 330 F in a deep pan.
Lightly coat chicken pieces with potato starch and deep-fry them until done.
Remove the chicken and drain on paper towels.
Serve and enjoy.