Peel and chop the potatoes into bite-sized pieces, then soak them in water and drain.

Cut the yellowtail fillet into bite-sized pieces.

Heat 1 tsp of salad oil in a pot over medium heat, add the yellowtail, and cook until browned. Remove the fish and wipe off excess oil.

Add the remaining 1 tsp of salad oil to the pot, heat, and stir-fry the potatoes until coated with oil.

Add the seasoning mixture (sake, mirin, sugar, water) to the pot and bring to a boil. Cover and simmer on low heat for 7–8 minutes.

Add soy sauce and the browned yellowtail to the pot. Cook over medium heat for another 5–6 minutes.