Step 1

Remove bones from chicken, leaving the skin on. Cut chicken into 1-1/2-inch pieces. In a shallow dish, combine sake, soy sauce, mirin and ginger. Add chicken and turn to coat. Cover and refrigerate for 30 minutes. Drain chicken, discarding the marinade.

Step 2

In a deep fryer or electric skillet, heat 2 inches of oil to 325°F. Place cornstarch in a shallow dish. Add chicken, a few pieces at a time, and toss to coat; shake off excess. Fry chicken, a few pieces at a time, just until golden brown, about 1-1/2 minutes. Drain on paper towels.

Step 3

Increase the heat of the oil to 350°. Use a metal fine mesh strainer to remove any fried bits from oil. Fry the chicken thighs again, a few pieces at a time, until dark golden brown, about 1 minute. Drain on paper towels. If desired, serve with mayonnaise.