Lay the ham skin side up on a cutting board. Use a sharp boning knife to make a horizontal cut halfway up, from the narrow end of the ham at the back toward the cross-section of bone that shows in front. Cut off and discard any extra rind.
Trim along the bone to remove it from the ham; if a little meat remains on the bone, that's okay. If the shank bone splits into 2 bones, remove the smaller one as well.
Close up the ham to form a tidy roast, then turn it over. Use a 4-foot-long piece of kitchen twine to tie the roast like a neat package (horizontally, then vertically).
Combine the apple juice, 1 bottle of the red wine, the salt, 1 cup of the honey and the dark brown sugar in a clean (preferably new) plastic bucket, stirring until the salt and sugar have dissolved. Submerge the tied ham in the brine and refrigerate for 2 days: a full 48 hours, no cheating. If any part of the ham sticks out of the brine, turn the ham halfway through the brining process, or use a dinner plate with a heavy can on top to keep the ham submerged.
Remove the ham from the brine; discard the brine. Rinse the ham under cool water. (At this point, the ham has been salt-cured and can stay in the refrigerator, wrapped in plastic wrap and butcher paper, for up to 1 week.)
Thoroughly rinse the bucket, then fill it with fresh, cool water. Submerge the cured ham in the water for 24 hours in the refrigerator: 1 full day, no cheating. Again, if any part of the ham sticks out of the water, turn the meat halfway through soaking process or use the plate-can contraption to keep it submerged.
Position an oven rack in the lowest part of the oven. Preheat the oven to 350 degrees. Have a large roasting pan at hand.
Arrange the orange slices in the bottom of the roasting pan (overlapping is okay). Set the ham on top of them, then pour the remaining bottle of wine into the pan. Sprinkle or place the allspice berries, cloves, cinnamon sticks and rosemary sprig around the ham. Also drizzle the remaining 1/4 cup honey both onto the ham and into the wine.
Cover the roasting pan with its lid, or seal it tightly with aluminum foil, and place on the lowest oven rack. Roast for 2 hours.
Uncover the pan and roast for 1 hour, basting the ham with the pan juices every 20 minutes.
Transfer the ham from the hot roasting pan to a large carving board. Cut it open and discard the twine. Cut off and discard the rind (which will be too salty to eat and quite purple), leaving a thin layer of fat on the meat. The whole thing will be quite hot: You can let it rest for a few minutes so you don’t burn your fingers.
Return the ham to the pan and roast uncovered for 1 to 1 1/2 hours, basting every 20 minutes, until an instant-read meat thermometer inserted into the center of the ham registers 170 degrees.
Transfer the ham to a cutting board and let stand at room temperature for 10 minutes before carving. Discard the contents left in the roasting pan.
From Bruce Weinstein and Mark Scarbrough, authors of "Ham: An Obsession With the Hindquarter" (Stewart, Tabori & Chang, 2010).
Tested by Bonnie S. Benwick.