Pat chicken thighs dry with paper towels. Heat vegetable oil in a large, heavy-bottomed pot or Dutch oven over medium-high heat until shimmering.

Brown the chicken thighs skin-side down for 4-5 minutes until golden, then flip and brown the other side for 3-4 minutes. Remove chicken and set aside.

In the same pot, add crushed garlic and sauté for 1 minute until fragrant. Add soy sauce, dark soy sauce, vinegar, bay leaves, and peppercorns.

Return chicken to the pot along with any accumulated juices. Add water until chicken is mostly covered. Bring to a boil.

Reduce heat to medium-low, cover, and simmer for 30-35 minutes until chicken is tender and cooked through.

Remove the lid and increase heat to medium. Continue cooking for 10-15 minutes until sauce reduces and becomes glossy, occasionally spooning sauce over chicken.

Optional: Stir in brown sugar during the last 2 minutes for extra caramelization. Remove bay leaves before serving.

Serve hot over steamed rice, spooning extra sauce over the chicken and rice.