Pork Chine is a squarish area across the backbone between the shoulder blades that holds tender meat.
It may or may not come attached to a rack of pork (pork loin), Often, it is trimmed off to allow easier carving at the table.
It is always cut off when making a crown roast of pork, to allow the two rib sides to be tied together. Some suggest in this case asking the butcher for the chine bone anyway, and to place it under the crown roast during to cooking to help prevent the bottom of the roast from burning.
One side of the Chine has fat on it; the other backbone.
In England, it is sometimes cured, rendering the meat pink and salty, then stuffed with leeks, onion, lettuce, parsley, raspberry leaves, etc.
To stuff it, make a place for the stuffing to go by making 5 slashes from the fat to the bone through it without going all the way through (the vertebrae bone at the back would likely stop you, anyway.) Turn it around, and do the same on that other side. You pack the stuffing into the slashes.
Queen Victoria served chine of pork for Christmas dinner at Osborne House in 1897 (along with lamb, beef, soup, fish and mince pies.)
The English world "Chine" comes from the French word "échine" meaning "spine."
Sometimes "Chine" is used as a verb to describe a technique involving a butcher loosening or removing the bone on a rack of pork to make carving easier.