Prepare the Chicken Broth Base: Rinse the chicken backs and wings thoroughly under cold water to remove any impurities. Place them in a large stockpot (at least 6-liter capacity). Add 3.5 liters (15 cups) of cold water.

Bring the chicken to a boil over high heat. Once boiling, you will see a lot of scum and impurities rise to the surface. Carefully skim off this scum with a fine-mesh sieve or a ladle. This is a crucial step for a clear and clean-tasting broth. Reduce the heat to low and maintain a gentle simmer.

Add Aromatics to the Broth: Peel and lightly smash the garlic cloves. Peel and slice the ginger into 1cm (1/2 inch) thick pieces. Wash the green parts of the scallions. Add the garlic, ginger, dried shiitake mushrooms, kombu, and scallion greens to the simmering stockpot.

Simmer the Broth: Cover the pot partially and let it simmer gently for at least 3 hours, or up to 6 hours for a richer flavor. Do not let the broth boil vigorously, as this can make it cloudy. Maintain a very gentle simmer, just a few bubbles rising occasionally. Skim off any additional scum that may appear.

Prepare the Chashu Pork: While the broth simmers, prepare the pork belly. Roll the pork belly tightly into a log shape and secure it with kitchen twine at intervals of about 2.5cm (1 inch). This helps it cook evenly and retain its shape.

Sear the Pork Belly: Heat 1 tbsp (15ml) of neutral oil in a heavy-bottomed pan or Dutch oven over medium-high heat. Sear the rolled pork belly on all sides until golden brown and slightly crispy. This step adds depth of flavor.

Braise the Pork Belly: Add the seared pork belly to a small saucepan or the same Dutch oven (if large enough). Pour in 250ml (1 cup) soy sauce, 125ml (1/2 cup) mirin, 60ml (1/4 cup) sake, 2 tbsp (25g) sugar, 2 smashed garlic cloves, and a 2.5cm (1 inch) piece of ginger. Add enough water to just cover the pork belly.

Simmer and Reduce the Braising Liquid: Bring the braising liquid to a gentle simmer. Cover the pot and cook on low heat for 1.5 to 2 hours, turning the pork belly every 30 minutes to ensure even cooking and coating in the sauce. The pork should be fork-tender. Once cooked, remove the pork belly from the liquid and let it cool slightly. Reserve the braising liquid.

Make the Tare (Ramen Seasoning Base): Strain the reserved braising liquid from the chashu pork into a clean saucepan. You should have about 250-300ml (1 to 1.25 cups) of concentrated liquid. This is your Shoyu Tare. If it seems too salty, you can dilute it slightly with a little water. Gently heat the tare but do not boil.

Prepare the Ajitsuke Tamago (Marinated Eggs): While the pork cools, prepare the eggs. Bring a small pot of water to a rolling boil. Gently lower 4 large eggs into the boiling water using a spider strainer. Cook for exactly 6 minutes and 30 seconds for a perfectly jammy yolk. Immediately transfer the eggs to an ice bath to stop the cooking process. Once cooled, carefully peel the eggs.

Marinate the Eggs: In a small container or zip-top bag, combine the peeled eggs with about 125ml (1/2 cup) of the cooled chashu braising liquid (or a mixture of soy sauce, mirin, and water if the braising liquid is too salty). Ensure the eggs are submerged. Marinate in the refrigerator for at least 4 hours, or preferably overnight.

Finish the Broth: Once the chicken broth has simmered sufficiently, carefully strain it through a fine-mesh sieve lined with cheesecloth (if possible) into a clean pot. Discard the solids. You should have about 2.5 to 3 liters (10 to 12 cups) of clear, flavorful broth. Season the broth with salt to taste. You can also add a splash of toasted sesame oil for extra aroma.

Prepare the Toppings: Thinly slice the cooled chashu pork. Halve the marinated eggs lengthwise. Thinly slice the green onions. Prepare the nori sheets and menma (if using).

Cook the Ramen Noodles: Bring a large pot of unsalted water to a rolling boil. Add the ramen noodles and cook according to package directions, usually 2-4 minutes for fresh noodles, or longer for dried. Be careful not to overcook them; they should be al dente. Drain them thoroughly.

Assemble the Ramen Bowls: For each serving bowl, add 2-3 tbsp (30-45ml) of the Shoyu Tare to the bottom. Ladle about 500-600ml (2 to 2.5 cups) of the hot chicken broth over the tare and stir gently to combine.

Add Noodles and Toppings: Add the drained, hot ramen noodles to the broth. Arrange the sliced chashu pork, halved marinated egg, nori sheets, menma (if using), and sliced green onions on top of the noodles. Serve immediately.