Shimesaba is a pickled mackerel topping for nigiri sushi, but can also be enjoyed on its own. The best time to fish for mackerel is in the late autumn, when the meat is fatty.
When you fillet the mackerel into two pieces, place each on a makisu (bamboo rolling mat) in a dish. Sprinkle generously with salt on both sides, then wrap and chill for 2-3 days. If you want the flavour to be a little lighter, you can chill it overnight only.
While it is chilling, combine the following:
1 cup rice vinegar
3 tbsp sugar
2 tsp shoyu
Boil and stir continuously so the sugar doesn’t burn, then remove from heat and pour into a baking dish, enough to submerge the mackerel.
Remove the mackerel from the fridge and rinse. Dip each fillet into a mixture of water and rice vinegar, then rinse again. Pat dry with a paper towel and tweeze any small bones out. Most of the bones will be in the centre of each fillet.
rinse again and place each, skin down, into the dish with the vinegar and sugar mixture. Wrap and rest for about 35 minutes, until the fish becomes whitish pink.
remove and pat dry, then remove the skin by peeling it back. Slice into thin pieces and serve!