Step 1

Place chicken, scallops, anchovies, shrimp, bonito flakes, half the ginger, and kombu in an electric pressure cooker. Add water; close and lock the lid. Select the Soup setting; set timer for 90 minutes according to manufacturer's instructions. Allow 10 to 15 minutes for pressure to build.

Step 2

Release pressure using the natural-release method according to manufacturer's instructions, 10 to 40 minutes. Strain broth through a colander or fine-mesh sieve. Skim the fatty oil off the top of the broth.

Step 3

Combine soy sauce, mirin, sake, green onions, bonito flakes, sugar, garlic, and kombu in a medium saucepan over high heat. Bring to a boil. Reduce heat to low and simmer until flavors blend, about 10 minutes. Strain tare sauce through a fine-mesh sieve into a bowl.

Step 4

Pour 2 tablespoons of tare sauce into a large bowl. Ladle in about 2 cups of broth. Add 1/6 of the ramen noodles. Repeat with remaining tare, broth, and ramen.