Prepare the Tofu: Drain tofu well and pat dry with paper towels. Wrap with a clean kitchen towel and press gently for 10–15 minutes to remove excess moisture.
Coat the Tofu: Cut tofu into bite-sized cubes. Lightly coat each piece in potato starch, shaking off any excess.
Fry the Tofu: Heat oil in a skillet over medium heat. Once hot (around 340–350°F / 170–180°C), gently add tofu and fry until all sides are golden and crisp. Remove with a slotted spoon and drain on paper towels.
Make the Broth: In a small saucepan, combine dashi, soy sauce, mirin, and sugar. Bring to a simmer over medium heat, then reduce to low and keep warm.
Assemble the Dish: Place crispy tofu pieces in individual serving bowls. Ladle hot broth over the tofu. Garnish with grated daikon, scallions, bonito flakes, and ginger.
Serve Immediately: Enjoy while hot so the tofu stays crispy while soaking up the flavorful broth.