After the fish is boned, cut off both sides of the whole fish and divide it into two pieces. Then, the fish skin is facing down, and the fish tail is on the left, from tail to head. If it is large, the back of the knife should be tilted to the right as far as possible. At the same time, press the fish slightly with your left hand and cut the fish from the left palm with a knife. You can know the thickness of the fillets by feeling, but be careful not to cut your hands. )