Recipe: Radix Rehmannia Candied Date Pig Bone Soup - Prepare 12 taels of pork spine, 1 tael of Radix Rehmannia, 6 candied dates, and 2 slices of ginger. Wash Radix Rehmannia and candied dates. Wash and blanch the spine. Put 8 bowls of water, add all the ingredients to boil on high heat for half an hour. Change to low heat for 2 hours and season with salt.