Combine soy sauce, chicken stock, white wine vinegar, ginger, and sugar in a small saucepan.

Heat the mixture over low heat.

Pat the fish fillets dry and season with salt and pepper.

Prepare three shallow dishes: one with cornstarch, one with beaten eggs and salt, and one with bread crumbs and sesame seeds.

Dredge each fillet in cornstarch, shaking off excess.

Dip the fillet in the egg mixture, allowing excess to drip off.

Dredge the fillet in the bread crumb mixture, pressing to adhere.

Heat 1/4 inch of vegetable oil in a skillet over moderately high heat until it begins to smoke.

Fry the fillets, 2 at a time, for 45 seconds to 1 minute on each side, until golden brown.

Transfer the fillets to paper towels to drain.

Transfer the fillets to plates.

Bring the soy sauce mixture to a boil.

Spoon the soy sauce mixture over the fish fillets.

Serve immediately.