Place the horse mackerel with its head to the left and belly facing you. Use a knife to scrape off the scales from tail to head on both sides.

Lay the knife flat and remove the hard ridge (zeigo) near the tail on both sides.

Position the fish with its head to the left and belly facing you. Cut behind the pectoral and ventral fins diagonally until you hit the backbone. Flip the fish and repeat on the other side to remove the head.

Insert the knife along the belly from the vent to the anal opening and remove the internal organs.

Make a small incision in the membrane covering the bloodline and scrape it clean. Rinse and pat dry with paper towels.

Position the fish diagonally with the head side up. Cut along the backbone to separate the belly fillet.

Slide the knife along the backbone to separate the back fillet.

Flip the fish and repeat the process to separate the belly and back fillets on the other side.

Lift the fillets slightly and cut away any remaining flesh attached to the backbone.

Stack the fillets and remove the backbone completely.

Place the fillets skin-side down. Use the knife to lift and remove the belly bones by slicing thinly.

Repeat the process to remove the belly bones from the other fillet.