Step 1 In a small bowl, combine the shoyu or tamari with the mirin, ginger and garlic-chile paste and set aside. (Makes three-fourths cup dipping sauce.)
Step 2 Cut the pumpkin in half and scrape out the seeds. Cut it in half again and remove the skin. Cut each quarter crosswise into half-moon slices about one-fourth-inch thick.
Step 3In a wok or skillet, heat the oil for deep frying to 375 degrees.
Step 4In a bowl, while the oil heats, combine the egg yolk and club soda. Add 1 cup of the flour and whisk lightly but not until smooth; it should be lumpy and airy. Place the remaining flour in a shallow bowl.
Step 5Working in batches, dredge the pumpkin slices first in the flour, shaking off the excess, then in the batter. (If the batter gets too thick, add a little more club soda and whisk lightly.) Lay the battered pumpkin into the hot oil without crowding. Cook, turning once, until the pieces are crisp outside and tender inside and caramelizing around the edges, about 3 minutes. Drain on paper towels and serve warm with the dipping sauce.