Place 6 pounds of beef leg bones in a large bowl and wash them thoroughly under cold running water.

Soak the bones in cold water for 8 hours to draw out the blood. Change the water every 2 hours.

After soaking, drain the bones, rinse them, and place them in a large 10-quart pot. Add enough fresh water to cover the bones.

Bring the pot to a vigorous boil over high heat and parboil for 20 minutes to remove impurities.

Drain the murky water and transfer the bones to a strainer. Wash each bone individually under running water to clean off any scum.

Thoroughly wash and scrub the pot to remove all residue.

Return the cleaned bones to the pot and fill it with fresh water.

Bring to a boil over high heat, then reduce the heat to low, cover, and let it simmer.

Simmer for 10-20 hours in total, refilling with water as it boils down. The video shows two simmering sessions of 10 and 9 hours. The broth will turn from yellow to a rich, milky white.

Strain the finished broth into a new pot to remove bones and any small particles.

Let the broth cool completely. The fat will rise to the top and solidify.

Skim off and discard the solidified layer of fat.

Portion the defatted, gelatinous broth into freezer-safe containers for long-term storage.

To serve, reheat the desired amount of broth until steaming hot.

Ladle the hot broth into a bowl and garnish with chopped green onions.

Season to taste with salt and ground black pepper.

Add some cooked rice directly into the soup and enjoy your hearty meal.