Rub the chicken both inside and out with the peppercorns and ginger. Marinate the chicken with the soy sauce, rice wine and brown sugar for at least 3 hours in the refrigerator, turning it several times.
Heat a wok until very hot. Add the oil and, when the oil is hot enough, remove the chicken from the marinade (reserving the marinade), and deep-fry for 6 minutes or until brown all over. Remove and drain on kitchen paper.
Pour off any excess oil, add the marinade with the stock, salt and crystallized sugar, and bring to the boil. Return the chicken to the pan, cover and braise the chicken in the sauce for 35–40 minutes, turning once or twice.
Remove the chicken from the wok and allow it cool a little before chopping it into bite-size pieces. Pour the sauce over the chicken and serve immediately.