Yakitori:

Up to one day in advance, put the sweet potato in a small pot, add enough water to cover and bring to simmer over medium high heat. Reduce the heat and cook just until fully tender, about 8 minutes.

Prepare the grill to cook over medium high heat and lightly rub the grill grates with vegetable oil.

Leave the wingettes unskwered for now. Season the wingettes lightly with salt and grill, skin side down and covered, until fully cooked and slightly crispy, about 15 minutes. Let them cook to touch.

Meanwhile, toss the sweet potato and shishitos with the oil and 1/2 tsp salt. Skewer the sweet potato slices lengthwise; skewer the chicken thigh and spring onion so they alternate on the skewer.

Reserve the wingettes on baking sheet. Season the chicken thigh and liver lightly with salt. Grill (it’s best if the exposed skewers aren’t directly over the flame), turning over once, just until lightly golden and fully cooked, 5 - 8 minutes.

Transfer the skewers to the baking sheet with the wingettes. Generously brush the chicken tight, liver, wingettes and meatballs all over with teriyaki sauce.

Serve immediately with spice powder for sprinkling.

For chicken meatballs.

Prepare the meatballs :

Combine the chicken, spring onion, yam, ginger, sake, salt, egg yolks and white peppers in a small mixing bowl. Mix firmly with your hands until the ingredients are well distributed. The mixture will be much looser than that for the typical Western meatball.

One by one, form the meatballs and add them to the boiling water. Spoon a generous tablespoon of the meatball mixture onto your palm, use the spoon to form it into an approximately 1 1/2 inch ball, add carefully spoon it into the water.

Generously brush the meatballs with teriyaki sauce and grill, turning over once and occasionally brushing on more sauce, until they are lightly charred, about 3 minutes. Serve immediately.

For teriyaki sauce:

Combine the ingredients in a small pot, bring to a boil over high heat, and reduce the heat to maintain a gentle simmer. Cook for about 8 minutes so the aromatics have a chance to infuse their flavour into the liquid. Strain, discarding the solids.

The sauce keep in an airtight container in the fridge for up 2 weeks.