Drizzle oil over the lamb shanks; rubbing it into the meat with your fingertips.

Add salt, sugar, five-spice powder, and pepper to a small bowl; stir to mix or use your fingers to mix.

Sprinkle the rub all over the lamb, patting it onto the meat with your fingers.

To make the barbecue sauce: add bbq sauce, hoisin sauce, rice wine, and sriracha in a nonreactive saucepan over medium heat; bring to a simmer; let simmer 10-15 minutes, until thick and richly flavored; set aside.

Set up grill for indirect grilling and preheat to medium-low; **for gas grill, place the wood chips in the smoker box or in a smoker pouch and run the grill on high until you see smoke, then decrease heat to medium-low.

When ready to cook, place the lamb shanks, on their side, in the center of the hot grate, over the drip pan and away from the heat; cover the grill.

Smoke roast the lamb shanks for 1 hour.

Wrap each shank in foil and continue cooking until very tender, 45 minutes to 1 ¼ hours more.

When the shanks are fully cooked, the meat will have pulled back from the shank bone and will be tender enough to pull apart with your fingers; internal temperature should be about 180°.

During the last 15 minutes or so, unwrap the shanks and brush them with some of the sauce.

Transfer the grilled lamb shanks to a platter and serve with the remaining barbecue sauce.