Place chicken thighs between plastic wrap and pound to an even 1/2-inch thickness. Season both sides generously with salt and let rest for 15 minutes.

Set up three shallow dishes: combine flour, garlic powder, white pepper, and 1 tsp salt in the first; whisk eggs and milk in the second; place panko in the third.

Make katsu sauce by whisking together ketchup, Worcestershire sauce, soy sauce, mirin, and sugar in a small bowl. Set aside.

Heat oil in a large, heavy-bottomed pot or deep skillet to 340-350°F. Use a thermometer to monitor temperature.

Dredge each chicken piece in flour mixture, shaking off excess, then dip in egg wash, and finally coat thoroughly in panko, pressing gently to adhere.

For extra crunch, dip coated cutlets back in egg wash and panko one more time. Let rest on a wire rack for 15 minutes.

Carefully place 2 cutlets in hot oil and fry for 3-4 minutes per side until deep golden brown and internal temperature reaches 165°F.

Transfer to a wire rack over paper towels to drain. Repeat with remaining cutlets, monitoring oil temperature between batches.

Slice katsu into strips and serve immediately over shredded cabbage with katsu sauce and steamed rice.