Place salmon fillets in large baking pan. Combine soy sauce, mirin, and sake in a small bowl and pour over salmon pieces to marinate for 10 minutes. Drain salmon, reserving marinade.
Heat the broiler and brush rack lightly with oil. Place fish on rack, skin side up, and brush pieces lightly with marinade. Grill until skin is lightly browned and crispy, about 4 minutes.
Turn salmon pieces and brush again lightly with the marinade. Grill until the salmon is just cooked through and the flesh flakes easily with a fork, about 4 minutes.
Remove fish to serving plates and spoon remaining marinade over top. Serve immediately with grated daikon and rice.
For equally delicious Scallop Teriyaki, substitute 500 g (1 lb) trimmed large scallops. For Grilled Teriyaki Vegetables, use assorted vegetables such as asparagus, eggplants, red bell peppers, and shiitake mushrooms.