Boil saké and mirin in a saucepan for 30 seconds to remove alcohol.
Dissolve miso and sugar into the liquid, then transfer to a bowl to cool.
Marinate cod fillets in the cooled mixture in the fridge for 24 to 48 hours.
Preheat grill to high and oven to 200°C.
Grill the wiped cod for 2-3 minutes, then bake for 10 minutes.
Heat vegetable oil in a heavy saucepan until a bread cube sizzles.
Fry sliced savoy cabbage for 45 seconds until crisp, drain, and season with sugar and salt.
Combine sliced pointed cabbage and coriander in a bowl.
Pound the remaining dressing ingredients in a mortar and toss with the cabbage.
Serve cod on a bed of fried cabbage topped with the dressed cabbage.