Using a fork, pierce the chicken through the skin several times to allow the sauce to penetrate, and to prevent shrinkage during cooking. In a large, deep frying pan, heat a tablespoon of oil over medium-high heat. Brown the chicken, skin-side-down, for 3–5 minutes. Reduce the heat to low, turn the chicken over, then cover and cook for 10 minutes. Transfer the chicken to a plate.
To make the teriyaki sauce, whisk together all the sauce ingredients until the sugar has dissolved. Pour into the pan and bring to the boil. Whisking constantly, boil for 2–3 minutes, or until thickened slightly. Return the chicken to the pan and cook for about 15 minutes, or until the sauce has reduced to a glossy syrup. You will need to turn the chicken several times to completely coat it with the sauce.
To serve, slice the chicken and drizzle with any remaining sauce. Sprinkle the coriander over the top.