Above picture is main dish for a dinner of one day, grilled fish dipped in miso (Saikyo-zuke) and Japanese style omelet (Tamago-yaki).
Normally Saikyo-zuke is cooked with Saikyo miso and dip fish meat in miso based sauce for 2 or 3 days in refrigerator.  It is popular especially in Kansai area (west part of Japan).
However Miso is well know as miso soup which is one of the most popular Japanese foods, it can be used not only for miso soup, but also as condiment for many foods.

However popular fish for Saikyo-zuke is a Spanish mackerel, I cooked sea bream meat at this time.  But Saikyo miso is expensive so I used reasonable white miso instead.

Ingredients

For sauce :

• miso (white type)  100g
• sake (for cooking use)   15ml
• mirin  15ml
• salt   a little

fish meat  (white meat)

1) cook miso based sauce :  mix all the ingredients for sauce.  Salt is an adjustment for taste.  If you feel too much sweet, put some salt.

2) dip fish meat in the sauce.  Smear sauce around the fish.  Then it leave in refrigerator for 1 or 2 days.

3) Wipe all miso sauce around fish.

4) Grill the fish on low heat.  Miso can be burned easily so please be careful.

I think heating 5 or 6 min. for each side will be good.

Usually we eat grilled fish with soy sauce, but Saikyo-zuke is dipped in the sauce and it has enough taste.  We eat it without soy sauce.
Normally, Saikyo-zuke is cooking white meat fish so you can try any kind of fish.

Enjoy meal!

Note:
Miso is very traditional Japanese food.  According to Wikipedia, the first record in document about miso seems to be around AD700.
There are several types because every region has their original.  Most popular types are red, white and also “awase” type.  “Awase” means mix of red and white.