Broth:

1. Place the chicken, pork bones, and pork fat in a large stock pot. Add enough water to fully cover. Cover and bring to a boil over high heat.
2. Drain the bones and wash off any dark marrow or coagulated blood under cold water.
3. Rinse the pot, return the bones, and add the remaining broth ingredients. Add water to barely cover. Cover and bring to a boil over high heat.
4. Simmer covered on low for 6–12 hours on the stove, or 12–18 hours in a slow cooker. Check the first 10–15 minutes to ensure it is barely simmering.
5. During the last 30 minutes to 1 hour, place the 5 oz of pork fat in a sieve set in the broth; cover and cook. Drain the fat and finely mince it.
6. Skim some or all of the fat from the finished broth (easiest after refrigeration).

Pork belly (chashu):

1. Preheat the oven to 250°F (121°C). Place the pork belly in a saucepan, add water to cover, and bring to a boil.
2. Drain and remove any scum.
3. Return the pork belly to the saucepan with the remaining chashu ingredients. Cover and bring to a boil over high heat.
4. Transfer to the preheated oven and cook for 5 hours, shaking the pan every hour to ensure even coating.
5. Insert a skewer — if there is no resistance, it is ready. Cook longer if desired.
6. Cool completely, then chill in the refrigerator (with the eggs) so the pork absorbs more flavor and is easier to slice.
7. When ready to serve, cut the strings, slice the pork, and briefly reheat in hot ramen broth.

Marinated eggs:

1. Bring enough water to cover the eggs to a boil in a saucepan.
2. Reduce heat to medium, gently add the eggs, and simmer for exactly 6 minutes.
3. Drain and peel the eggs under cold water.
4. Place the peeled eggs in the cooled chashu braising liquid. Soak a paper towel in the liquid and drape it over the eggs to keep them submerged. Marinate for 4–12 hours in the refrigerator alongside the pork belly.
5. When ready to serve, carefully slice the eggs in half and briefly warm in hot ramen broth — do not overheat.

Assembling:

1. Bring the broth to a boil and add seasoning gradually to taste.
2. Arrange noodles in a bowl and add sliced chashu, a halved marinated egg, minced pork fat, and your choice of toppings and garnishes. Serve immediately.