As another member pointed out this translates literally to "miso pickle" (See also: https://en.wikipedia.org/wiki/Tsukemono) and is a style of curing fish in a miso/mirin/sake marinade. It is very simple and extremely delicious. I should point out that this recipe comes from a Japanese cookbook call the The Zen Kitchen by ex-masterchef winner Adam Liaw - a fantastic book (and author) containing many mouth-watering recipes for fish. I would strongly encourage members to look out for it.
All the ingredients should be available from your local supermarket. You will, however, require some clean muslin cloth which I purchased from a kitchenware store. The muslin cloth makes it easier to remove the fish without any marinade actually clinging to the fish which, apparently, can burn and disrupt the flavour when cooking.
1 cup miso paste
2 tablespoons mirin
1 tablespoon cooking sake
kingfish. (skin attached, filleted and pinboned)
Olive oil for brushing.
Combine the miso, mirin and sake in a bowl to make the marinade. In a shallow dish layer a bit less than half of the marinade on the bottom. Place muslin cloth over the paste and then place the fish on the cloth. Layer another piece of muslin over the fish and then cover this with the remaining marinade. Cover with cling wrap and place in the fridge. Ideally, you should allow the fish to cure for 1-2 days.
Remove the fish from the marinade and scrape off any marinade mixture (do not wash it). Apparently, you can re-use the marinade but it didn't look very appetising to me.
Baking or grilling is the best method - avoid direct heat. I made a bed of onions on the barbecue and simply laid the fish skin side down, brushed the fish with a little olive oil, turned off the burners under the hot plate (leaving the burners under the grill on) and closed the lid. Temperature rose to 200C and it took less than ten minutes to cook - this will, of course, depend upon the thickness of the flesh. Thicker cuts than my tail-end will likely require a little longer. A hot oven should work equally well I imagine.
Serve with some steamed vegetables. Enjoy!