Soak the short ribs in water for an hour to remove the iron in the meat.
Meanwhile, prepare the radish, garlic, onion, ginger, Korean pear, carrots, and mushrooms.
Place the meat in a big pot and add the water, soy sauce, brown sugar, peppercorns, cinnamon stick, radish, scallions, mirin, and sake.
Blend the onion, garlic, Korean pear, and ginger, then add them to the pot.
Boil the seasoned meat on high heat.
Once the meat is on a rapid boil, place it on medium to simmer for 45 minutes. Make sure to remove any scum floating on top.
At the 20-minute mark, add jujubee, mushrooms, carrots, and chestnuts. Let it simmer for another 25 minutes.
Once the time is up, check the tenderness of the beef, remove from heat, then skim out excess oil.
Drain the sauce in a clean bowl and remove the cinnamon stick, scallion stalks, peppercorns, etc.
Optional: You can boil the sauce to thicken it up and turn it into a nice glaze.
Plate the meat and vegetables, pour the sauce back in, and serve it with rice and kimchi. Enjoy!