Combine soy sauce, ketchup, chicken broth, brown sugar, garlic, & ginger in a medium bowl and whisk until well combined.
Place meat in a zip-close plastic bag or in a container with a lid.
Reserve 3/4 - 1 cup of marinade in a small container for basting.
Pour remaining marinade over chicken, making sure chicken is submerged or covered by marinade.
Marinate for 24 hours.
Heat grill to 350˚F
Remove chicken from marinade and place on the grill.
Every 15 minutes flip the chicken and baste with marinade.
Remove chicken when the internal temperature reaches 165˚F. Approximately, 45 minutes to 1 hour to cook.