In a bowl, combine hoisin sauce, sweet soy sauce, soy sauce, oyster sauce, honey, brown sugar, sesame oil, and five spice powder.
Place pork tenderloin(s) into a zip lock bag, add sauce to zip lock bag. Refrigerate and marinate for 8 hours or more.
Fire up charcoal grill. Place pork tenderloins to the side of the burning coals so that it will be exposed to the heat indirectly. Save the marinate.
Turn pork over every 20 minutes and brush additional marinate onto tenderloin after every flip. This is how to get a layer of sticky glaze on the pork. Once internal temperature reaches 165 degrees F on multiple spots on the tenderloin, pork is done.
Slice tenderloin into thin slices