Take a sauce pan and add 80 ml sake, 2 tbsp yellow miso paste (awase), 2 tbsp sugar, 1 tbsp garlic paste, ½ tbsp toasted sesame oil, 1 tsp dashi granules and 1 tsp chili powder.
Mix well and bring to a boil over a medium heat, stirring occasionally. Once it starts to bubble, reduce the heat and simmer for 5 minutes until thickened, then remove from the heat.
Cut the white parts of 2 Japanese leek (naganegi) into 2-3cm pieces (approximately 1 inch).
Cut the 350 g pork shoulder into cubes so that the thickness is equal to the size of the leeks.
Start preheating your grill or broiler on high. While you wait, push the pork and Japanese leek pieces onto skewers, starting with pork and alternating between pork and leeks. There should be 3 pieces of pork and two pieces of leek on each skewer. Sprinkle with salt and pepper on both sides.
Once the grill is preheated, lightly grease the wire rack and arrange the skewers on so that they will be underneath the heat source. Grill for 5 minutes on each side.
Brush the top with the prepared miso sauce and grill for 2 minutes, then repeat on the other side.