Finely chop the Napa Cabbage, sprinkle with Salt and let sit 10 minutes to draw out moisture; then squeeze the cabbage dry in a clean towel or sieve.
Mince the Garlic Chives, Garlic and Ginger.
In a mixing bowl, combine the Ground Pork with the minced chives, garlic and ginger, then add Soy Sauce, Sake, Sesame Oil, Sugar and Ground White Pepper; mix until the filling becomes slightly sticky and well incorporated.
Fold the squeezed cabbage into the pork mixture, taste and adjust seasoning with a little more salt or soy if needed, then chill the filling for 10–15 minutes to let the flavors meld.
Prepare to assemble: place a Round Gyoza Wrapper on your palm, put about a teaspoon of filling in the center, moisten the wrapper edge with Water, fold and pleat to seal (keep a small bowl of water nearby for sealing).
Heat a nonstick skillet over medium-high heat and add about 1 tablespoon Neutral Oil; arrange gyoza flat-side down without crowding and cook 2–3 minutes until the bottoms are golden brown.
Carefully pour in approximately 1/4 cup water, cover immediately and steam for 4–5 minutes until the filling is cooked through and the water has mostly evaporated; remove the lid and cook 1 more minute to re-crisp the bottoms.
If desired, finish with a light drizzle of additional sesame oil for aroma, then transfer the gyoza to a serving platter.
Make the dipping sauce by mixing Soy Sauce and Rice Vinegar (about 1 tbsp each), add a splash of Water or a pinch of Sugar to balance, and finish with a few drops of Rayu to taste.
Serve the gyoza hot with the dipping sauce and enjoy.
