Nanbanzuke: Japanese Vinegar-Marinated Fried Fish and the Portuguese Culinary Legacy

Ingredients

• 600 g small whole fish (shishamo, aji, iwashi, or small sole) or smelt, or cut chicken karaage pieces, well-dried before frying
• For the nanban-zu marinade
• 120 ml komezu (rice vinegar)
• 80 ml mirin
• 40 ml soy sauce
• 100 ml dashi
• 1–2 dried togarashi chilli, whole or sliced into rounds
• 15 g sugar
• For the vegetables
• 1 medium onion, very thinly sliced, rinsed in ice water and drained
• 1 medium carrot, julienned
• 1 stalk negi (Japanese long onion), thinly sliced on the diagonal
• For frying
• 500 ml vegetable oil, for deep-frying
• 60 g light batter (katakuriko or plain flour), for dusting or coating the fish

Method

1. 1
   Pat the fish or chicken pieces thoroughly dry with paper towel. Any residual moisture will create steam on contact with oil, collapsing the crust before it meets the marinade. The surface must be visibly and completely dry to the touch.
2. 2
   Combine the komezu, mirin, soy sauce, dashi, sugar, and dried togarashi in a wide, shallow container — large enough to hold the fried pieces in a single layer. Stir until the sugar dissolves. Add the ice-water-rinsed, drained onion slices, carrot julienne, and negi. The marinade should smell clean and sweet-sour with a low note of soy; taste it — it must register acid brightness followed by sweetness, with no single element dominant.
3. 3
   Heat the vegetable oil to 160 °C. Dust the fish lightly in katakuriko or flour and lower into the oil. Fry until cooked through — the flesh will no longer flex when pressed and the coating will be pale gold. Remove and drain briefly.
4. 4
   Raise the oil temperature to 185 °C. Return the fish for 30 seconds. This is where the dish lives or dies: the second fry builds the hard, sealed crust that can withstand submersion in marinade without immediately turning to paste. The pieces must emerge deeply golden, audibly crackling, and rigid — not pale or yielding.
5. 5
   Transfer the fried pieces directly from the oil into the cold marinade while they are still at full frying temperature. Do not rest them. The temperature differential drives the vinegar solution into the food; a piece allowed to cool even briefly will absorb far less. Press the vegetables gently around and over the fish so every surface is in contact with marinade.
6. 6
   Marinate at room temperature for 30 minutes for a crisp-interior result with surface absorption, or cover and refrigerate for up to 24 hours for a fully marinated, deeply flavoured piece. Do not exceed 24 hours — prolonged acid exposure breaks down the fish to a mushy consistency. At 30 minutes, the marinade should have visibly clouded slightly from the fry oil; at 24 hours, the vegetables should be limp and fragrant with vinegar.
7. 7
   Serve cold, directly from the refrigerator at approximately 8 °C. Arrange fish and vegetables together. The finished dish should present a saturated, glossy surface; the flesh should be yielding but not disintegrated; the marinade should pool beneath as a dipping sauce.