Preparation

• In a food processor, pulse the garlic, ginger, and peppercorns until finely chopped, scraping down the bowl occasionally, about 3 minutes. Add the vinegar, soy sauce, and oil. Process until combined, about 30 seconds.
• Put the chicken in a large zip-top plastic bag, and pour in the marinade. Press the air out of the bag and seal tightly. Turn the bag to distribute the marinade. Refrigerate for at least 2 hours or up to 4 hours.
• Heat the grill to 500°F. When hot, brush the grill grate clean. Prepare the grill for direct and indirect cooking, and reduce the temperature to medium heat, as close as possible to between 350°F and 375°F.
• Meanwhile, remove the chicken from the marinade, letting the excess drip back into the bag; reserve the marinade. Pour the marinade into a medium saucepan, and stir in the sugar and bay leaves. Bring to a boil over high heat. Reduce the heat to medium high, and continue to boil until the liquid is reduced to 3/4 cup, whisking occasionally and lowering the heat if necessary so that it doesn’t burn, 8 to 10 minutes. Remove the glaze from the heat.
• Keeping the lid closed as much as possible, grill the thighs skin side down first over direct medium heat until golden-brown, turning once, 10 to 12 minutes. Move the chicken pieces over indirect medium heat, skin side up. Brush with the glaze. Continue to grill with the lid
  closed until an instant-read thermometer inserted into the thickest part of the thighs and not touching the bone registers 160°F to 165°F, 20 to 25 minutes. Halfway through cooking time, turn the thighs over to skin side down, and brush with more of the glaze. Remove from the grill. In a small saucepan, bring the remaining glaze to a boil again. Serve the thighs on a bed of herbed rice, if you like, and drizzle with the extra glaze.