If your julienned ginger pieces are limp, put them in ice water for a while to stiffen them up. This technique of Nitsuke can be used to cook other kinds of fish too. Fish with white flesh is the best for Nitsuke and the fish is usually cooked with bones intact.
“Nitsuke” is a popular and delicious way to cook fish in Japan where the fish is stewed in soy sauce, mirin and sake. (It is also our favourite way of cooking fish because there isn't much mise en place and the sauce complements the strong taste of fish!)
Fish simmered in soy-based sauce is called ‘ sakana no nitsuke ’ (魚の煮付け) in Japanese, where ‘sakana’ (魚) is fish and ‘ nitsuke ’ (煮付け) is simmered dish. The word ‘ no’ is equivalent to ‘of’. Nitsuke is actually the same thing as ‘ nimono’ (煮物).
Since Nitsuke is a generic term for simmered fish, the name of the dish always uses with the name of the fish at the beginning, like today’s dish Karei no Nitsuke. ‘ Karei’ (カレイ or 鰈) is flounder in Japanese.