1, prepare fresh big bones, yam, onion ginger and seasonings, as shown in the figure:

2. Blanch the big bones with water first to remove the blood and dirt inside, as shown in the figure:

3. Rinse the blanched big bones with water and control the water for later use, as shown in the figure:

4, onion cut into large pieces, ginger cut into large pieces for later use, as shown:

5, blanched big bones and chopped onion ginger into the casserole, as shown in the figure:

6. Pour the seasonings such as star anise, cinnamon, fragrant leaves and tsaoko into the casserole, as shown in the figure:

7. Pour an appropriate amount of water until it is too big, then cover it and put it on the fire to start cooking. Turn the fire to a low heat for one hour, as shown in the figure:

8. Peel and cut the yam into pieces. Do not cut the yam in advance to prevent oxidation and blackening, as shown in the figure:

9. Pour in yam, add salt and continue to simmer for half an hour, as shown in the figure:

10, such a nutritious yam bone soup would be fine.