Make a light dashi: place a 4–6" piece of Dried Kombu in 3 cups cold water and let it soak for 20–30 minutes (or longer for deeper flavor).
Gently heat the kombu infusion over medium-low heat and remove the kombu just before the water reaches a simmer to avoid bitterness.
Add a generous handful of Katsuobushi to the hot water, turn off the heat, and let the flakes steep for 4–6 minutes; then strain the liquid through a fine sieve or cheesecloth into a bowl. This is your dashi base — let it cool to room temperature.
In a clean bowl or jar combine 1 cup of Soy Sauce with about 1/2 cup total of citrus juices — for example 1/4 cup Yuzu Juice and 1/4 cup Sudachi Juice — then stir in 2 tablespoons Rice Vinegar and 2 tablespoons Mirin.
Pour about 1 cup of the cooled dashi into the soy-citrus mixture, stir to combine, and taste. Adjust balance: add more citrus for brightness, more soy for saltiness, or a splash more mirin for sweetness.
Transfer the ponzu to a covered container and refrigerate for at least 4 hours, preferably overnight, to allow the flavors to meld. If you prefer a clearer sauce, strain again before bottling.
Store refrigerated and use within 1–2 weeks. Shake or stir before serving; ponzu is excellent as a dipping sauce, marinade, or finishing drizzle.
