Slice halibut as described in above recipe and arrange on plates.
Prepare the vinegar mixture in above recipe, adding the mitsuba, and coat the fish. Proceed with remaining recipe above, using grated daikon in place of sprouts and scallions in place of the red onion. Serve immediately with ponzu sauce alongside the halibut for dipping.
Combine all ingredients in a bowl and let stand 24 hours. Strain through a cheesecloth and mature 3 months in a cool, dark place, or in the refrigerator.
c.1997, M.S. Milliken & S. Feniger, all rights reserved