Add pork bone into a large stocking pot and enough water to submerge them completely.
Bring to boil then simmer the pot for at least an hour. Skin any impurity that is floating to the surface.
After an hour, take out about 90% of the stock and set aside for later use.
Then add pork fat and enough water to submerge everything completely, bring to boil again.
Keep the pot boiling hard at all time on medium high heat to create such milky and cream texture for the soup.
Cook the mixture for 2 hours. During the process, when the water reduces and no longer cover pork bones and fat, add more water immediately. Approximately 30 to 40 minutes between every cycle.
After 2 hours has passed, continue cooking the stock for at least an hour. But this time, instead of adding fresh water to the pot, using 90% of stock was set aside to add to the pot.
Repeat the process of adding more water when it is reduced below the bones. Approximately 20 to 30 minutes between each cycle.
When you can no longer get the soup milkier and creamier, turn off the heat. Strain the stock and set aside.