Step 1: Rinse the fish fillets under cold running water and blot dry with paper towels. Arrange the fillets in a nonreactive baking dish just large enough to hold them.

Step 2: Prepare the marinade. Pound the garlic, ginger, cilantro leaves and root, if using, and sugar to a paste in a mortar with a pestle. Or puree in a minichopper or food processor. Work in the fish sauce, sake, sesame oil, salt, and pepper. Spoon the marinade on both sides of the fillets. Cover with plastic wrap and let marinate in the refrigerator for 30 minutes to 1 hour, turning once or twice.

Step 3: Set up the grill for direct grilling and preheat to high. When ready to cook, oil the fish basket, if using, or brush and oil the grill grate. Place the fillets in the basket; if grilling directly on the grill grate, brush or spray the fillets themselves with oil.

Step 4: Place the fish or the fish basket on the hot grate. Grill until each side of the fillets is browned and cooked through, 4 to 6 minutes per side. Because the fillets tend to be fragile, I don’t generally bother with rotating them to apply a crosshatch of grill marks. If grilling directly on the grate, brush the tops of the fillets with oil before gently turning them with a spatula. To test for doneness, press a fillet with your finger; it should break into clean flakes when fully cooked. Another test is to insert a metal skewer in the side of a fillet. When it is done, the skewer will come out very hot to the touch after 20 seconds.