Bring the vinegar, lime juice, miso, soy sauce, sugar
, ketchup, yuzu
kosho, garlic and ginger
to a simmer
in a medium saucepan
over medium heat. Reduce the heat if necessary to keep at a low bubble for 20 minutes.
Remove the pan from the heat and stir in the bonito
for 5 to 10 minutes; the flakes will wilt and soften in the pan. If a smoother sauce is desired, blend
or puree. Use immediately, or refrigerate in a nonreactive container for up to 2 days.