Step 1

Place about 3 1/2 pounds pork bones in a large pot and add enough cool water to cover by about 1 inch. Bring to a boil over high heat. Reduce the heat to maintain a simmer and cook for 30 minutes.

Step 2

Drain and rinse the scum off the bones. Place in a 6-quart or larger Instant Pot or electric pressure cooker. Add 8 cups cool water. Lock the lid on and check that the valve is set to seal. Set to cook for 240 minutes (4 hours) on HIGH pressure. It will take about 15 minutes to come up to pressure. Meanwhile, make the chashu, ajitsuke tamago, and tare.

Step 3

Place 1 (1-pound) piece boneless pork shoulder in a medium saucepan. Prepare the following, adding each to the saucepan as you complete it: Trim and cut 1 medium Japanese or 1 small leek (all parts) crosswise into 3-inch pieces. Cut 1 (1-inch) piece ginger crosswise into 1/4-inch-thick rounds (no need to peel). Crush 4 garlic cloves with the flat part of a knife and peel if needed.

Step 4

Add 1 cup soy sauce, 1 cup mirin, 3/4 cup water, and 1/2 cup sake. Bring to a boil over high heat. Meanwhile, cut a sheet of aluminum foil that will fit inside the saucepan, then tear a little slit in the center.

Step 5

Reduce the heat to maintain a simmer. Place the foil in the saucepan, pressing it directly onto the surface of the ingredients. Simmer for 30 minutes. (This is a good time to boil the eggs and make the tare.)

Step 6

Remove the foil and set aside. Fip the pork, cover again with the foil, and simmer until knife-tender, 1 to 1 1/4 hours more.

Step 7

Turn off the heat. Remove the foil and flip the pork. Cover again with the foil and let cool in the liquid for 2 to 3 hours. Transfer the pork to a sheet of plastic wrap, tightly wrap it up, and refrigerate until ready to use.

Step 8

Pour the cooking liquid through a fine-mesh strainer set over a bowl; discard the contents of the strainer. Reserve the cooking liquid for the ajitsuke tamago.

Step 9

Fill a medium saucepan with water and bring to a boil over high heat. Slowly lower 4 cold large eggs into the water one at a time. Return to a boil. Reduce the heat to maintain a simmer and cook for 8 minutes. Meanwhile, prepare an ice water bath by filling a medium bowl halfway with ice and water.

Step 10

Remove the eggs from the water with a slotted spoon and place in the ice water bath. Let sit until the eggs are cool to the touch. Peel the eggs and place in a container that will fit the eggs somewhat snuggly or a sandwich-sized plastic zip-top bag.

Step 11

Add enough reserved chashu cooking liquid to halfway to cover the eggs (about 1/3 cup). Add enough room-temperature water so the liquid completely cover the eggs, then give it a gentle stir. Cover or press the air out of the bag and then seal.

Step 12

Let the eggs marinate in the refrigerator for at least 2 but no more than 24 hours. (Remove the eggs from the cooking liquid after 24 hours and refrigerate in a separate container.)

Step 13

Crush 6 garlic cloves with the flat part of a knife and peel. Place the garlic, 1/4 cup plus 1 tablespoon usukuchi soy sauce, 1/4 cup plus 1 tablespoon fish sauce, 1 tablespoon plus 2 teaspoons mirin, 1 (about 4-inch) piece dried kombu, and 1 dried shiitake mushroom in a small saucepan. Bring to a boil over medium heat. Reduce heat to maintain a simmer and cook for 10 minutes.

Step 14

Remove the saucepan from the heat. Let cool to room temperature, about 30 minutes. Discard the garlic, kombu, and shiitake. Measure the tare: You should have about 1/4 cup (if you have less, add water to get to 1/4 cup).

Step 15

Turn the pressure cooker off and let the pressure naturally release for 15 minutes. Manually release any remaining pressure. If the valve is sputtering and releasing stock rather than steam, close the valve, let the pressure naturally release for 10 minutes, and then try again.

Step 16

Open the lid and stir well. Loosen any leftover marrow in the bones with a skewer or chopstick. Turn on the “Sauté” function on high and cook uncovered, stirring occasionally, for 30 minutes.

Step 17

Pour through a fine-mesh strainer set over a large heatproof bowl and discard the contents of the strainer. Let the stock sit for a few minutes so the fat can rise to the top. Spoon off and discard most of the fat. Measure the remaining stock: You will need 6 cups. Add more water as needed to get to 6 cups, or simmer on the stovetop or in a clean Instant Pot until you get down to 6 cups if you have too much. (You can cool and refrigerate the stock at this point if not using right away.)

Step 18

When ready to serve, bring a large pot of water to a boil. Meanwhile, place 4 large pieces dried wood ear mushrooms in a small bowl, add enough warm water to cover, and let sit for at least 15 minutes; remove from the water and thinly slice. If the stock is cold, scrape most of the hardened fat off the top. Return the stock to a simmer on the stovetop or in a clean Instant Pot. For each serving (up to 4), place 2 teaspoons of the tare in a deep serving bowl (with a capacity of at least 4 cups). Unwrap and thinly slice the chashu. Halve the eggs lengthwise. Thinly slice 1 medium scallion. Finely grate 2 garlic cloves.

Step 19

Add 1 (3- to 4-ounce) portion ramen noodles for each serving desired to the hot water and cook according to package directions. Just before the noodles are done, add 1 1/2 cups of the hot pork stock to each bowl, and gently stir to combine. Taste and season with more tare 1 teaspoon at a time as needed.

Step 20

Drain the noodles very well, then add to the bowls. Arrange a few slices chashu (you will have extra), the egg, scallions, garlic, and wood ear mushrooms over the noodles. Garnish with beni shoga and toasted sesame seeds. Serve with rice vinegar if desired.