Combine all ingredients for the filling in a large bowl.

Add ground pork to the bowl and mix well with your hands until fully combined.

Finely chop the Chinese cabbage (or cabbage), and massage in a modest amount of salt. This will help remove excess moisture.

Squeeze the cabbage firmly to remove the extra water. Discard the water.

Mince the Chinese chives and white Japanese leek.

Add the prepared vegetables into the pork mixture in the bowl.

Add 1 tablespoon of katakuriko (potato starch) to the filling and mix thoroughly. This will help bind the ingredients.

Take a gyoza skin and place a spoonful of filling in the center.

Fold the gyoza skin in half to enclose the filling, creating a half-moon shape.

Cover your left thumb from the right to make folds along one edge of the gyoza, securing the filling and creating a decorative crimped edge.

Warm up an electric griddle or frying pan over medium heat, then spread a thin layer of vegetable or sesame oil on the surface.

Carefully align the gyoza on the prepared surface, ensuring they are not overcrowded.

Pan-fry the gyoza until the bottoms are browned and crispy. This should take about 5-7 minutes.

Once browned, add 1 cup of water to the griddle or frying pan and immediately cover with a lid. The steam will cook the filling.

Cook until the water is almost completely reduced and the gyoza are cooked through. This should take about 8-10 minutes.

If desired, drizzle some sesame oil over the gyoza during the last minute of cooking for added flavor and crispiness.

The gyoza are ready to eat when they are crispy and golden brown on the bottom and the filling is cooked through.

Prepare the dipping sauce by combining soy sauce, vinegar, and mirin in a 3:2:1 ratio. Add a few drops of sesame oil, grated ginger, minced garlic, and a pinch of ichimi spice to taste.