Soak the oxtail in water for a minimum of 2 hours to remove the iron in the meat. Drain and place in a heavy bottom pot.
Put water in the pot and boil the oxtail on high heat for 10 minutes then drain again to remove all the impurities from the meat.
Fill the pot back up with water and bring it up to boil again. Once boiling, turn the heat to medium and let the oxtail boil for 2-3 hours.
Keep checking back every hour and add more water leaving an inch from the brim when it reduces. Make sure to remove the scum and oil that floats on top.
After 2-3 hours of boiling, place 5 cups of the broth and the big chunks of oxtail in another heavy bottom pot. Let the remaining broth boil for 12-24 hours, check this blog post for more instructions.
In the other pot, to make the braised oxtail, put soy sauce, sugar, pepper, cinnamon stick, Korean radish, scallions, soju, mirin, and MSG. Mix well.
Blend garlic, onion, ginger, and pear, then add to the pot.
Place potatoes, carrots, mushrooms, jujubee, and chestnuts in the pot as well.
Mix then cover and let the oxtail braise for 30 minutes until the meat and vegetables are fork-tender.
Before plating, remove any oil floating on top of the dish.
Serve with rice and kimchi. Enjoy!