1. To make the gyoza dough, place the flour into a large mixing bowl.
2. In a small saucepot, bring 150ml (150g) water to a boil. Immediately take it off the heat and stir in a generous pinch of salt.
3. Pour the salted boiling water into the flour and combine with a wooden spoon. When the dough is cool enough to handle, knead it by hand inside the bowl until it comes together. If the dough appears very dry, add additional water, about 1 Tbsp at a time, but be careful not to over hydrate.
4. Transfer the dough to a clean work surface and knead until smooth, about 5 to 8 minutes. Lightly dust the bowl with cornstarch and place the dough back inside. Cover with a damp dish towel and let it rest for an hour at room temperature.
5. To make the filling, remove the core and slice the cabbage as thinly as possible. Transfer to a medium bowl and season to taste with salt. Massage the salt into the cabbage, squeezing the leaves often to help release moisture.  Set aside for a few minutes to allow the cabbage to soften.
6. Place the pork in a large mixing bowl. Squeeze as much liquid out as possible from the cabbage. Discard the liquid and add the cabbage to the pork. Add the green onions, garlic, ginger, and 2 tsp tamari. Season generously with salt and mix thoroughly by hand. 
7. Divide the dough in half, and roll each half into a 1” thick cylinder. Wrap each cylinder with plastic wrap and leave at room temperature for 15 to 30 minutes.
8. To make the sauce, whisk together ¼ cup and 2 Tbsp tamari, rice vinegar, mirin, sesame oil, honey and sesame seeds in a large measuring cup or bowl.  If you prefer a spicy sauce, add Thai chili.  Set aside until ready to serve.
9. Divide each dough into 12 equal-sized pieces and cover with a damp dish towel to prevent them from drying out. 
10. Working with one ball at a time, roll out evenly into a 3 ½-inch circle with a rolling pin. Dust with cornstarch as needed to prevent the dough from sticking. Place a 3” straight round cookie cutter over the dough and cut out a circle. Repeat with the remaining dough and stack the circles on top of each other, dusting each with a little cornstarch. Keep the rounds covered under a damp dish towel. 
11. Place 2 tsp of the filling in the center of the wrapper. Rub a tiny amount of water along the edges of the dough and gently fold over to create a half moon shape. Before crimping the dough together to seal, fold small pleats along the top dough and then firmly press that scalloped edge against the bottom dough to enclose the filling. Repeat with the remaining dough. Store extra pork filling in an airtight container in the fridge or freezer for future use.
12. In a large well-seasoned cast iron pan or non-stick skillet, heat 2 tablespoons of oil over medium-high heat until hot and shimmering.  Working in batches, arrange one layer of gyoza 1” apart with the crimped edges facing up. Without moving the gyoza, allow the bottoms to start browning. 
13. Carefully pour in ¼ cup of water and immediately cover the pan. Reduce the heat to medium and steam gyoza for 3 minutes. Remove the lid and continue to cook over medium-high heat until all the water has evaporated and the bottoms are deep golden brown and crisp.
14. Transfer to a platter and serve with the sauce. 

‍