Heat vegetable oil in a large pot over medium-high heat; cook and stir garlic in hot oil until fragrant. Sear chicken until golden brown, about 3 minutes per side. Stir vinegar, peppercorn, and bay leaves into pot and bring to a boil.
Pour water and soy sauce into mixture and reduce heat to low. Cover and simmer until chicken is tender and no longer pink in the center, about 45 minutes. Stir in more water if sauce is too salty.
