Rinse chicken bones and place them in a large pot covered with water. Bring to a boil over high heat and simmer for 10 minutes. Remove from heat and drain, rinsing bones and pot.

Place chicken bones back in the pot with 8 cups of water, ginger, garlic, and 3 stalks of green onion. Cover the pot, bring to a boil, reduce heat to low, and simmer for 2 hours. Skim fat and keep warm.

Combine pork belly with sake, soy sauce, mirin, water, sugar, ginger, garlic, and the stalk of green onion in a pot. Cover and bring to a boil. Reduce heat to low and simmer for 2 hours or until pork is fall-apart tender.

Combine all ingredients for tare in a small saucepot and bring to a boil over medium heat. Reduce heat to low and simmer for 5 minutes. Strain, discarding ingredients. Let cool.

Cook noodles according to package instructions and drain. Pour 1 tablespoon tare, 2 cups chicken broth, and 1 teaspoon MSG per bowl. Add noodles, thinly shaved onion, radish sprouts, scallions, and a boiled egg. Serve immediately.