Place the short ribs in a large bowl, cover with cold water, and soak for 30 minutes. Drain and rinse under cold running water.

Bring 2 liters of water to a rolling boil in a large Dutch oven. Add the drained ribs and blanch for 5 minutes. Skim off any foam that rises.

Drain the ribs in a colander and rinse each piece under cold water. Pat dry with paper towels and set aside. Wipe out the Dutch oven.

In a medium bowl, whisk together the soy sauce, grated Asian pear, minced garlic, grated ginger, gochujang, brown sugar, mirin, and black pepper until combined.

Pour in the beef broth and stir once to mix. Taste the sauce. It should be savory, lightly sweet, and have a gentle heat.

Return the blanched ribs to the Dutch oven in a single layer as much as possible. Pour the braising sauce over the top.

Bring to a boil over medium-high heat, then reduce to low. Cover and braise for 1 hour, turning the ribs once halfway through.

After 1 hour, add the daikon, carrots, rehydrated shiitake mushrooms, and chestnuts if using. Stir gently to coat with the sauce.

Cover again and continue braising on low heat for 30 minutes, until the daikon is tender when pierced with a chopstick and the ribs pull easily from the bone.

Remove the lid and increase heat to medium. Cook uncovered for 10-15 minutes, stirring occasionally, until the sauce reduces to a thick, glossy glaze that coats the ribs.

Turn off the heat. Drizzle the sesame oil over the top and stir gently once to incorporate.

Rest the pot off the heat for 10 minutes before serving. Garnish with sliced spring onions, sesame seeds, and pine nuts.