Season the pork with salt and pepper. In large Dutch oven, heat oil over medium-high heat, 2 turns of the pan. Brown the pork evenly all over. Add dried mushrooms, ginger, garlic, carrots, leek, stock and 1 quart water and bring to boil. Reduce heat to a low simmer, cover and cook pork 2-2 1/2 hours to very tender, skimming occasionally.
Remove pork and rest, strain the stock and keep warm. Pull pork and cover to keep warm.